FINAL REPORT 

Synthesis of Active Traffic Management 

Experiences in Europe 

and the United States

Submitted to: 

FHWA 

Prepared by: 

Parsons Brinckerhoff 

March 2010 

Publication # FHWA-HOP-10-031 
Foreword 

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Technical Report Documentation Page 

1. Report No. 

FHWA-HOP-10-031 

2. Government Accession No. 3. Recipient's Catalog No. 

4. Title and Subtitle 

 Synthesis of Active Traffic Management 

 Experiences in Europe 

 and the United States 

5. Report Date 

 May 2010 

6. Performing Organization Code 

7. Author(s) 

 Chuck Fuhs (Parsons Brinckerhoff) 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 

 Parsons Brinckerhoff 

 1 Penn Plaza 

 New York, NY 10119-0002 

(performed as a subconsultant to Cambridge Systematics)

10. Work Unit No. (TRAIS) 

11. Contract or Grant No. 

 DTFH61-06-D-00004 

12. Sponsoring Agency Name and Address 

 U.S. Department of Transportation 

 Federal Highway Administration 

 Office of Operations (HOP) 

 1200 New Jersey Avenue, SE 

 Washington, DC 20590 

13. Type of Report and Period Covered 

 Final Report 

14. Sponsoring Agency Code 

 HOP 

15. Supplementary Notes 

 FHWA COTM - Jessie Yung. 

16. Abstract 

This synthesis report describes both US and European techniques in Active Traffic Management 

(ATM). The primary focus of this synthesis is on European experience, which in some cases dates back 

a number of years. This report provides a compilation of lessons learned, experiences, operational 

results, and benefits associated with active traffic management applications. The applications included 

for discussion are primarily those that include variable speed management (also called speed 

harmonization or lane control in Europe), shoulder or line management, junction control, and 

directional routing. The report concludes with a discussion of the potential benefits and challenges of a 

system-wide application of techniques to actively manage traffic and a listing of initial implementations 

of European strategies in the US. 

17. Key Word 

Active Traffic Management, High Occupancy 

Toll, High Occupancy Vehicle, Lane Control, 

managed lanes, speed harmonization, variable 

speed limit, congestion management, pricing, 

operations 

18. Distribution Statement 

No Restrictions. 

19. Security Classif. (of this report) 

unclassified 

20. Security Classif. (of this page) 

unclassified 

21. No. of Pages 

 35 

22. Price 

NA 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

Synthesis of Active Traffic Management Experiences in Europe and Related Articles i 

March 2010 

Table of Contents 

1.0 Introduction ............................................................................................................. 1

1.1 Report Purpose ............................................................................................ 1

1.2 2006 Scan Tour Summary ............................................................................ 1

2.0 What Is Active Traffic Management; Why and When Is it Used? ............................ 3

2.1 European Traffic Management Strategies .................................................... 3

2.2 US-based Traffic Management Strategies .................................................... 4

3.0 US Techniques ........................................................................................................ 5

3.1 Ramp Metering ............................................................................................. 5

3.2 Managed Lanes ............................................................................................ 6

3.3 Speed Harmonization ................................................................................... 7

3.4 Hard Shoulder Running .............................................................................. 12

3.5 Junction Control .......................................................................................... 15

3.6 Dynamic Re-routing .................................................................................... 16

3.7 Traveler Information ................................................................................... 18

3.8 Summary .................................................................................................... 18

4.0 System Level Applications .................................................................................... 19

4.1 Overall Roadway Management .................................................................. 19

4.2 Spot Roadway Management Strategies ..................................................... 20

4.3 Incremental Implementation ....................................................................... 21

4.4 Adaptation to Existing US ITS and Traffic Operations Investments ............ 22

5.0 Initial US-Based Implementation of European Traffic Management 

Strategies .............................................................................................................. 26

5.1 Under Study ............................................................................................... 26

5.2 Implementation ........................................................................................... 26

6.0 References ............................................................................................................ 27

List of Figures 

Figure 1. Speed Harmonization Signing in the Netherlands ............................................ 7

Figure 2. Dynamic Speed Limits in Randstad Area ......................................................... 8

Figure 3. Queue Warning—Side-Mount Congestion Icons ............................................ 11

Figure 4. Hard Shoulder Running When Active and Inactive ........................................ 13

Figure 5. Emergency Pull-Outs Associated with Hard Shoulder Running ..................... 13

Figure 6. Speed-Volume Relationship of Temporary Shoulder Use .............................. 14

Figure 7. Junction Control at an Exit with Hard Shoulder Running ................................ 15

Figure 8. Junction Control On-Ramp Schematic ........................................................... 16

Figure 9. Dynamic Route Information in The Netherlands ............................................. 17

Figure 10. Relationships Between ATM Strategies ....................................................... 19
Synthesis of Active Traffic Management Experiences in Europe and Related Articles ii 

March 2010 

List of Abbreviations and Acronyms 

ATM Active Traffic Management 

CCTV Closed Circuit Television 

DMS Dynamic Message Sign 

FHWA Federal Highway Administration 

GP General Purpose 

HOT High Occupancy Toll 

HOV High Occupancy Vehicle 

ITS Intelligent Transportation System 

LCD Lane Control Display 

LED Light Emitting Diode 

MUTCD Manual on Uniform Traffic Control Devices 

NTCIP National Transportation Communications for ITS Protocol 

O&M Operations and Maintenance 

PM Preventive Maintenance 

PS&E Plans, Specifications and Estimate 

SOP Standard Operating Procedure 

SOV Single-Occupant Vehicle 

TDM 

TMC 

Travel Demand Management 

Traffic Management Center 

TMS Transportation Management System 

UPS Uninterruptible Power Supply 

US United States 

VMS Variable Message Sign 

VSL Variable Speed Limit 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 1 

March 2010 

1.0 Introduction 

1.1 Report Purpose 

This synthesis report describes both US and European techniques in Active Traffic Management 

(ATM). 

The primary focus of this synthesis is on European experience, which in some cases dates back a 

number of years. This report provides a compilation of lessons learned, experiences, operational 

results, and benefits associated with active traffic management applications. The applications 

included for discussion are primarily those that include variable speed management (also called 

speed harmonization or lane control in Europe), shoulder or line management, junction control, 

and directional routing. The report concludes with a discussion of the potential benefits and 

challenges of a system-wide application of techniques to actively manage traffic and a listing of 

initial implementations of European strategies in the US. 

1.2 2006 Scan Tour Summary 

In June 2006, a group of eleven US transportation professionals representing planning, design, 

and operations visited five European nations to study how they were addressing freeway 

congestion using dynamic or actively managed traffic management techniques. The trip was 

sponsored by the International Technology Scanning Program, a partnership of AASHTO, 

FHWA, and the National Cooperative Highway Research Program of TRB. The trip purpose was 

to examine congestion management programs, policies, and experiences from the perspectives of 

national, state, and local transportation agencies. 

The scan team found that through the deployment of these specific traffic management 

techniques, agencies in Denmark, England, Germany, and The Netherlands exercise increased 

control over their roadway facilities and are able to better optimize their infrastructure 

investment to meet customer needs. Depending on the location and the combination of strategies 

deployed, specific benefits as a result of this congestion management approach include: 

• An increase in average throughput for congested periods of 3 to 7 percent; 

• An increase in overall capacity of 3 to 22 percent; 

• A decrease in primary incidents of 3 to 30 percent; 

• A decrease in secondary incidents of 40 to 50 percent; 

• An overall harmonization of speeds during congested periods; 

• Decreased headways and more uniform driver behavior; 

• An increase in trip reliability; and 

• The ability to delay the onset of freeway breakdown. 

Nine key recommendations were identified by the scan team that would be applicable to 

congestion management in the United States. The following are the scan team’s primary 

recommendations (Mirshahi, et al., 2007): 

1. Promote active management to optimize existing infrastructure during recurrent and nonrecurrent congestion. 

2. Emphasize customer orientation and focus on trip reliability. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 2 

March 2010 

3. Integrate active management into infrastructure planning and programming processes. 

4. Make operations a priority in planning, programming, and funding processes. 

5. Develop tools to support active management investment decisions. 

6. Consider public-private partnerships and other innovative financing and delivery 

strategies. 

7. Provide consistent messages to roadway users. 

8. Consider pricing as only one component of a total management package. 

9. Include (ATM consideration) as part of the overall management of congested facilities. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 3 

March 2010 

2.0 What Is Active Traffic Management--Why and 

When is it Used? 

Active Traffic Management is generally regarded as an approach for dynamically managing and 

controlling traffic demand and available capacity of transportation facilities, based on prevailing 

traffic conditions, using one or a combination of real-time and predictive operational strategies. 

When implemented together with traditional traffic demand management strategies, these 

operational strategies can help to maximize the effectiveness and efficiency of a roadway and 

result in improved safety, trip reliability and throughput. A truly active management philosophy 

dictates that the full range of available operational strategies be considered; including the various 

ways these strategies can be integrated together and among existing infrastructure, to actively 

manage the transportation system to achieve system performance goals. This includes traditional 

traffic management and ITS technologies commonly applied in the US, as well as new 

technologies and non-traditional traffic management technologies more commonly applied in 

other parts of the world. 

Active management techniques are utilized throughout the world, but the focus of this synthesis 

is on those strategies utilized in Europe and the US. While the European and US strategies are 

different, in many cases they are complementary and may be combined to provide greater 

benefits than when implemented separately. The following sections describe strategies that are 

used in Europe and the US to enhance and support the management of roadway facilities either 

in an individual or combined manner to maximize efficiency and effectiveness of a single 

roadway facility or a larger roadway network. 

2.1 European Traffic Management Strategies 

The following list provides a high-level description of strategies currently being deployed in 

Europe to actively manage traffic: 

• Speed Harmonization/Lane Control: utilizing regularly spaced, over lane speed and 

lane control signs to dynamically and automatically reducing speed limits in areas of 

congestion, construction work zones, accidents, or special events to maintain traffic flow 

and reduce the risk of collisions due to speed differentials at the end of the queue and 

throughout the congested area. 

• Queue Warning: utilizing either side mount or over lane signs to warn motorists of 

downstream queues and direct through-traffic to alternate lanes – effectively utilizing 

available roadway capacity and reducing the likelihood of collisions related to queuing. 

• Hard Shoulder Running: using the roadway shoulder (inside or outside) as a travel lane 

during congested periods to alleviate recurrent (bottleneck) congestion for all or a subset 

of users such as transit buses. Hard shoulder running can also be used to manage traffic 

and congestion immediately after an incident. 

• Junction Control: using lane use control, variable traffic signs, and dynamic pavement 

markings to direct traffic to specific lanes (mainline or ramp) within an interchange area 

based on varying traffic demand, to effectively utilize available roadway capacity to 

reduce congestion 

• Dynamic Re-routing: changing major destination signing to account for downstream 

traffic conditions within a roadway network or system. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 4 

March 2010 

• Traveler Information: providing estimated travel time information and other roadway 

and system conditions reports allowing travelers to make better pre-trip and in-route 

decisions. 

2.2 US-based Traffic Management Strategies 

The following list provides a high-level description of traffic management strategies that have 

been typically deployed in the US. 

• Ramp Metering: controlling the flow of vehicles entering a travel stream (typically 

freeway or highway facilities) to improve the efficiency of merging, and reduce 

accidents. 

• Lane Management (or Managed Lane): improving or facilitating traffic flow in 

response to changing roadway conditions. Lane management includes controlling use of 

lanes by vehicle eligibility (carpool or transit), access control, and price. 

• Variable Speed Limits: dynamically changing speed limit signs to adjust to changing 

roadway conditions, oftentimes weather related. 

• Shoulder Use: use of the shoulder by time of day for transit or HOV, and in some 

instances general purpose traffic, to provide improved mobility along or within congested 

corridors. 

• Pricing: managing traffic demand and flow using priced lane facilities, where traffic flow 

in the priced lane(s) is continuously monitored and electronic tolls are varied based on 

‘real-time’ demand. Pricing of roadway facilities can collect a toll from all users of the 

facility. In the case of high occupancy toll (HOT) lanes, transit and carpools with a 

designated number of occupants are allowed to use the priced lanes for free or a reduced 

rate. 

• Traveler Information: a variety of types of information provided to travelers (typically 

via variable message signs) to allow them to make informed travel decisions. Typical 

travel information includes travel times via alternative routes, and occurrence of incidents 

ahead. 

The following chapters describe the listed European and US management strategies in greater 

detail. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 5 

March 2010 

3.0 US Techniques 

As noted previously, ramp metering and managed lanes comprise the primary types of 

techniques currently under operation in the US that can be managed actively, with many 

metropolitan areas employing both ramp metering and managed lane facilities. Ramp meters are 

stop-and-go traffic signals placed at an on-ramp to control the frequency at which vehicles enter 

the freeway traffic stream. Managed lane facilities can include high occupancy vehicle (HOV), 

high occupancy toll (HOT), transit only lanes, and express lanes. They can be concurrent, 

contraflow or reversible lanes, whether operated part- or full-time. 

3.1 Ramp Metering 

Ramp metering, which maintains smooth freeway mainline flow by breaking up platoons of 

entering vehicles and/or limiting vehicle entry at entrance ramps, has been proposed and 

implemented in a number of metropolitan areas in and outside the US to mitigate freeway 

congestion due to merging vehicles. 

The primary objectives of ramp metering include managing traffic demand to reduce congestion, 

improving the efficiency of merging, and reducing accidents—all of which lead to improved 

mainline freeway flow. In some situations, high volume freeway mainline flow can 

accommodate disbursed merging vehicles, but often cannot handle groups of vehicles at once. 

Ramp meters may control ramp traffic based on conditions in the field or manually to optimize 

the release of vehicles entering the freeway facility. 

Ramp metering that is operated at pre-determined fixed-times of day is typically not considered 

an active management technique – while its operation can be demand based (on historical 

demand data), it does not manage the demand in a real-time active manner1

. Ramp metering that 

employs or is managed using an adaptive algorithm that is based on system-wide monitoring that 

controls the application of ramp metering is considered an active management technique. Ramp 

meters that are monitored, activated and adjusted based on traffic operations by staff at traffic 

management centers would be considered actively managed, regardless of the algorithm used by 

the specific ramp meter. 

The success of early ramp metering applications in US cities such as Chicago, Los Angeles, 

Minneapolis and Seattle led to the implementation and expansion of ramp metering systems in 

many other metropolitan areas in the US including Phoenix, AZ; Fresno, CA; Sacramento, CA; 

San Francisco, CA; San Diego, CA; Denver, CO; Atlanta, GA; Las Vegas, NV; Long Island, 

NY; New York, NY; Cleveland, OH; Lehigh Valley area, PA; Philadelphia, PA; Houston, TX; 

Arlington, VA; Miami, FL; and Milwaukee, WI; as well as in cities in other countries including 

Sydney, Australia; Toronto, Canada; and Birmingham and Southampton, UK. 

In 2000 an independent study on ramp metering was conducted in the Minneapolis-St. Paul area 

(Cambridge Systematics, 2001). The evaluation addressed traffic flow and safety impacts 

associated with turning off all 430 ramp meters for six weeks. Results released by the Minnesota 

Department of Transportation showed that without ramp meters there was: 

 

1

 It could be argued that even though a ramp metering system is set to start and stop at the same time every day, if it 

is actively monitored by operators and adjusted to adapt to conditions, and/or if the overall ramp metering algorithm 

is proactive in nature, then it could be considered actively managed. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 6 

March 2010 

• A nine percent reduction in freeway volume. 

• A 22 percent increase in freeway travel times. 

• A seven percent reduction in freeway speeds, which contributed to the negative effect on 

freeway travel times. The reliability of freeway travel time was found to decline by 

91 percent without ramp meters. 

• A 26 percent increase in crashes, which was averaged for seasonal variations. These 

crashes broke down to a 14.6 percent increase in rear-end crashes, a 200 percent increase 

in side-swipe crashes, a 60 percent increase in “run off the road” crashes, and an 

8.6 percent increase in other types of crashes. 

While ramp metering is more prevalent in the US, it is also employed in Europe. Germany has 

noted that ramp metering effectively prevents the drop in traffic speeds normally associated with 

merges and allows for the harmonization of traffic flow on major controlled access roadways. 

Ramp metering was found to reduce crashes with person and property damage by up to 40 

percent, with no negative effects on the adjacent roadway network. On highway A40, a test 

program from 1998–2002, showed a reduction in accidents of 55 percent, and a 65 percent 

reduction in severe accidents (translated from “Europe on Course—Telematics on German 

Roads” German Ministry for Transportation, Construction and Housing 2005). 

3.2 Managed Lanes 

A popular approach to mobility management in the US is managed lanes, which are defined as 

dedicated highway facilities or lanes in which operational strategies are implemented and 

managed. Many of the current strategies are not managed in real time, but with technology 

advances more real time applications are being considered and implemented. Managed lanes can 

facilitate traffic flow in response to changing conditions by controlling user eligibility, access 

and/or pricing. Traditional lane management strategies include high occupancy vehicle (HOV) 

lanes, high occupancy toll (HOT) lanes, express lanes and reversible lanes. Of the listed 

managed lane strategies, the only two that can currently be considered as “actively” managed are 

HOT lanes and express lanes that are dynamically priced. 

This chapter includes a description of European traffic management techniques with specific 

examples from Germany, Denmark, the Netherlands, and the United Kingdom. Information, 

experience and data were highly variable in their availability and therefore, some management 

techniques are discussed in greater detail than others. All techniques described include a 

definition of the technique and an associated benefits assessment. When information was 

available for a given technique, information on operational and safety considerations was 

included as well. 

The following European techniques are discussed: 

• Speed Harmonization/Lane Control: dynamically and automatically reducing speed 

limits in or before areas of congestion, accidents, or special events to maintain flow and 

reduce risk of collisions due to speed differentials. 

• Queue Warning: warning motorists of downstream queues and direct through-traffic to 

alternate lanes, to effectively utilize available roadway capacity and reduce the likelihood 

of collisions related to queuing.) 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 7 

March 2010 

• Hard Shoulder Running: using the shoulder (inside or outside) as a travel lane during 

congested periods to minimize recurrent congestion. Hard shoulder running can also be 

used to manage traffic and associated congestion immediately after an incident. 

• Junction Control: using variable traffic signs, dynamic pavement markings, and lane 

use control to direct traffic to specific lanes (mainline or ramp) based on varying traffic 

demand, to effectively utilize available roadway capacity and manage traffic flows to 

reduce congestion 

• Dynamic Re-routing: changing destination signing to account for downstream traffic 

conditions 

• Traveler Information: providing estimated travel time information and other conditions 

reports allowing for better pre-trip and in-route decisions 

3.3 Speed Harmonization 

Speed harmonization (also known as variable speed limits in the US) has been used in the 

Netherlands and Germany since the 1970s, where it is typically implemented on roadways with 

high traffic volumes, with a goal of improving traffic flow. In the Netherlands, speed 

harmonization has been used for many years for the purposes of creating more uniform travel 

speeds and managing traffic during adverse weather conditions. Lane control displays are used 

for mitigation of incidents, maintenance and construction. In Germany, approximately 200km 

(124 miles) of roadway are managed using speed harmonization and lane control. In Denmark, 

speed harmonization, also referred to as variable speed limits, is deployed to manage 

construction project-related 

congestion on the ring road 

around Copenhagen. 

Figure 1 shows speed 

`harmonization signing in the 

Netherlands, while Figure 2 

shows the Dutch signage 

application of the dynamic speed 

limit system in the Randstad area. 

In general, the European 

experience has been that at least 

one lane control display should 

be visible at all times for 

maximum effectiveness. In the 

Netherlands, gantries supporting 

speed controls are typically 

spaced an average of every 

1,600 feet. In Germany, overhead 

sign bridge spacing is every 

3,300 feet (1 km), but varies with 

installation and can extend 

farther, depending on sight distance. In addition to sight-distance and geometric considerations, 

cost may ultimately play a role in the spacing of lane control displays. Gantry spacing for the UK 

M42 motorway pilot project that implemented a combined speed harmonization and hard 

Source: Dutch Department of Transportation 

Figure 1. Speed Harmonization Signing in the 

Netherlands 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 8 

March 2010 

shoulder running installation was 

approximately every 1,600 feet 

(500 meters). Future UK managed 

motorway installations may 

ultimately consider a minimum 

spacing of approximately 2,600 

feet (800 meters) and a maximum 

spacing of 3,300 feet (1000 

meters) (UK Highways Agency 

Interim Advice Note 87/07, 2007). 

Lane control displays provide the 

flexibility to help manage 

incidents or address maintenance 

activities. When congestion is 

present, the speed limit is 

dynamically adjusted and 

displayed. When an incident 

occurs, a lane may be closed by 

showing a red ‘X’. Advance notice of an incident is usually provided by indicating to motorists 

that they should switch out of that lane. This is typically done by using a diagonal arrow pointing 

to a neighboring lane. In the Netherlands, when an incident occurs, they use a cocked arrow, 

followed by a red “X” to move drivers out of the lane. On the M42 motorway in the UK, lane 

control displays are typically enabled for four gantries upstream from the closure or incident, 

with the first indication being a reduction in standard operating speed, the second a further 

reduction in speed, and the following two gantries using cocked arrows to move drivers out of a 

closed lane(s). 

Critical to success of speed harmonization is the traveler’s trust in the real-time operation of the 

system, including how it is being operated, its reliability, and the sense that it is being 

implemented for a valid purpose that will result in true safety and travel time benefits. Hence 

traveler information and in many cases queue warning are treated as crucial components for 

maximizing effectiveness of this technique. Operating the system on a 24/7 basis also generates 

public trust in the system whenever conditions warrant, and these conditions do not necessarily 

mean 24/7 staffing of the operation center. 

Benefits Assessment 

Germany has perhaps the longest history of speed harmonization projects, dating back to the 

1970’s. Their experience has shown that speed harmonization results in lower accident rates and 

typically results in a modest (5-10 percent) increase in roadway capacity. This is accomplished in 

part because the variable speed limits decrease the likelihood of severe congestion by increasing 

the stability of traffic flow (translated from “Europe on Course—Telematics on German Roads” 

German Ministry for Transportation, Construction and Housing 2005). 

When implemented in Germany on the A5 motorway between Bad Homburg and 

Frankfurt/West, speed harmonization was associated with a 27 percent reduction in accidents 

with heavy material damage and a 30 percent reduction in personal injury crashes (Sparmann, 

Source: Stoelhorst and Havermans Centre for Transport and Navigation, 2008 

Figure 2. Dynamic Speed Limits in Randstad Area 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 9 

March 2010 

2006). In Bavaria, accidents were reduced by up to 35 percent, with 31 percent fewer crashes 

involving injuries (translated from “Europe on Course—Telematics on German Roads” German 

Ministry for Transportation, Construction and Housing 2005). 

In the Danish case, as a result of the traffic management applications implemented (speed 

harmonization, lane management and variable message system)—traffic loads on the 

surrounding streets were less than expected and accidents did not increase appreciably during the 

re-construction of the M3 Motorway, even though the existing roadway lanes were narrowed 

during the construction period (Wendelboe, 2008). 

England has also applied speed harmonization, known locally as Variable Mandatory Speed 

Limits (VMSL). On M-42, speed harmonization with hard shoulder running resulted in a seven 

percent increase in capacity and less overall congestion over the 12-month study period. 

Statistically valid safety analysis requires three years of data, but the initial results are 

encouraging (Mott MacDonald Ltd., 2008). 

Additionally, a number of countries have documented a reduction in vehicle emissions after the 

implementation of speed harmonization. In The Netherlands, local traffic emission reductions of 

NOx were in the 20 to 30 percent range and PM10 was reduced by approximately 10 percent in 

the four test locations. In the UK, initial results found that vehicle emissions were reduced 

between four and 10 percent depending on the pollutant, and fuel consumption was also reduced 

by four percent (Mott MacDonald Ltd., 2008). 

Operations 

In the UK, speed harmonization has been applied to the six-lane M42 motorway (three lanes in 

each direction) in the West Midlands near Birmingham. In locations where hard-shoulder 

running is also applied to the outside shoulder, speed harmonization is included for the hard 

shoulder lane as well. Speed harmonization in the three-lane sections is automatically activated 

based upon flow and speed thresholds, though operators may adjust the operation if required. In 

general, speeds are adjusted approximately three gantries (approximately 1,500 meters or nearly 

1 mile) back from the area of reduced speeds or an incident. 

Speed harmonization with hard shoulder running (four lanes) is also based on predefined flow 

and speed thresholds. However, activation is not automatic, since operators need to ensure that 

the hard shoulder running lane is not blocked by debris or stopped vehicles. When activated, the 

speed limit is 50 mph or less (Mott MacDonald Ltd., 2008). 

Operations for the Washington State Department of Transportation (WSDOT) speed 

harmonization/queue warning system will be similar to the UK M42 motorway system in that the 

over-lane speed and lane control signs are automatically activated based on identified thresholds. 

Under normal congested conditions reduced speeds will be shown on the over-lane signs and 

reduced speed warnings and information will be provided via side-mount signs and traditional 

VMS approximately two gantries (1 mile upstream) from congested conditions. The gantry 

immediately preceding the back of the queue will display the lowest designated speed on the 

over-lane signs. Over-lane signs on subsequent gantries within congested conditions will be 

turned off and the shoulder-mount and traditional VMS will provide regulatory and 

informational messages as necessary. Under incident conditions that include a lane blockage, 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 10 

March 2010 

approximately four gantries upstream from the lane blockage will be employed to first reduce 

traffic speeds and then divert traffic from the blocked lanes. 

Operations for the Minnesota Department of Transportation (MnDOT) intelligent lane control 

and variable speed limit system are generally similar to those discussed for the WSDOT system. 

Under normal congested conditions, two gantries prior to congested conditions will be engaged 

and five gantries prior to a blocking incident will be engaged, with the first two gantries 

displaying speed reductions and the remaining three displaying lane control information (Kary, 

2009). 

Enforcement and Compliance 

Enforcement of the speed harmonization system’s reduced speeds in the Netherlands and 

England is automated. The automated speed enforcement system in the Netherlands measures 

average speeds over a two to three km (1.2 to 1.8 miles) section of the highway. In England, 

digital cameras are being used to record the license plates of violators who do not comply with 

the reduced speeds shown on the over-lane signs. Not all digital cameras are actively monitored 

at any one time, but the randomness of monitoring helps promote widespread respect among 

motorists. The threshold for what constitutes a speed offense is also random, based on the 

number of observed offenses so that only the worst offenders are cited. 

Thus far, England’s experience on M42 near Birmingham illustrates high compliance with the 

posted speed limits using the Association of Chief Police Officers (ACPO) thresholds for 

enforcement. This threshold T is defined as being 10 percent higher than the posted speed S plus 

two mph, or: 

T =1.1× S + 2

Speed data were collected from January 2006 to September 2007 at 12 locations in each 

direction and analyzed applying the above thresholds for compliance with the posted speed limit. 

For speed limits of 50, 60, and 70 mph, compliance was 94 percent or better in all cases. For 

40 mph posted speed limits, compliance was 84% or better. On the hard shoulder running lane, 

compliance was 97 percent or better at a 50 mph speed limit and 93 percent or better at a 40 mph 

speed limit (Mott MacDonald Ltd., 2008). 

During the M42 pilot project study, surveys were performed to determine public awareness of 

signs and information. Each survey was split into two populations: local users and long distance 

users. Both groups had high (over 90 percent) awareness of the signs in the study section. 

However, they noted that some driver education is still necessary, particularly with the ‘lane 

ahead closed’ sign indicating that the lane was closing and drivers should therefore change to a 

neighboring lane. During 2007, a total of 25 percent of local users did not know the meaning of 

the sign (Mott MacDonald Ltd., 2008). 

Capital, Operations and Maintenance Costs 

Capital costs of speed harmonization can vary considerably by installation. This variance in cost 

is a result of the overall infrastructure approach to gantry/sign-bridge placement distances (1/4, 

to 1⁄2 to 3⁄4, to 1 mile spacing), the number of lanes being spanned, the type of roadway that 

gantries/sign-bridges are being place on (at-grade or structure), the application of over lane, 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 11 

March 2010 

variable message and side mount signage, and the need for new or additional ancillary equipment 

(power, fiber optics, data feed, etc). 

As an example of the difference in capital costs due to infrastructure, the M42 project in the UK 

is estimated in USD equivalent (USD equivalent based on 2008 exchange rates) per mile costs 

of approximately $18 million per mile (UK Department for Transport, 2008), which also 

includes the costs related to hard shoulder running. Whereas, the conceptual cost estimates for 

the Washington State speed harmonization/queue warning system were projected to range 

between $2.4 and $5.5 million per mile depending on the roadway segment (WSDOT, Active 

Traffic Management Conceptual Design and Cost Estimates, 2008). WSDOT developed an 

average conceptual cost estimate for a three-lane section of approximately $3.2 million per 

directional mile and approximately $4.0 million per directional mile for a five-lane section. It is 

important to note that the WSDOT costs do not include implementation of hard shoulder 

running. 

As is demonstrated by the information above, capital costs for these systems can vary 

dramatically depending on the desired system, the inclusion of shoulder operations, signage 

requirements, gantry/sign bridge spacing, upgrades to ancillary equipment, and associated 

emergency refuge areas if desired. Therefore, it is critical to develop the overall system concept 

first and then determine the system requirements and operational approach to fully understand 

and estimate system costs. Operation and maintenance cost variances are due to the level to 

which existing traffic management systems are already employed along the roadway, the 

operational philosophy employed for the proposed speed harmonization system and finally the 

integration of speed harmonization facilities and operations into an existing traffic management 

center. 

Queue Warning 

A key component of Germany’s speed harmonization system is the addition of queue warning. A 

congestion pictograph or icon is displayed on both sides of the gantries to alert motorists of 

congestion ahead (Figure 3). Alternatively, the pictograph may be displayed on an overhead 

DMS. The value of the system lies in being able to reduce the occurrence of incidents caused by 

the congestion. 

Queue warning systems are 

very frequently combined with 

speed harmonization systems 

given the large number of 

design elements they have in 

common. The Dutch system 

also incorporates queue warning 

in their speed harmonization 

system; motorists are alerted of 

downstream queues with 

flashing lights in addition to 

variable speed signs. As a 

result, there are few examples of 

queue warning systems 

Source: Hessen, Germany

Figure 3. Queue Warning—Side-Mount Congestion 

Icons 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 12 

March 2010 

operating in the absence of other traffic management strategies, which makes separate 

quantification of benefits and costs difficult. 

Benefits Assessment

In Germany, the pilot project queue warning system was implemented on the A8 motorway 

between Stuttgart and Ulm. Positive results measured from the pilot included fewer accidents 

and reduced accident severity, a considerable reduction of high travel speeds, harmonization of 

all driving speeds, closer headways and more uniform driver behavior, and a slight increase in 

capacity, when compared to other motorways. In general, motorists were found to drive with 

greater caution due to the increased awareness of oncoming risks and downstream queuing. The 

result of this successful pilot has been its broader implementation across Germany and the 

inclusion of this strategy in the overall approach to managing congestion (Sparmann, 2006). 

The Dutch have reported benefits of congestion warning (queue warning) in combination with 

speed harmonization in terms of a 15 to 25 percent decrease in primary accidents and a 40 to 50 

percent decrease in secondary accidents from their safety assessments in 1983 and 1996, as well 

as an increase in throughput of four and five percent (Middelham, 2006). 

3.4 Hard Shoulder Running 

In Germany, hard shoulder running (also called temporary shoulder use) is applied with speed 

harmonization typically to address recurrent congestion and bottlenecks, but can also be 

deployed for non-recurrent congestion or incidents. This strategy allows for additional capacity 

during congestion and has been in use since the 1990s. 

The Netherlands started using hard shoulder running in 2003 as part of a larger program to 

improve use of the existing infrastructure. The system on the M42 motorway in England utilizes 

the availability of the shoulder for travel rather than for emergency refuge only (Figure 4). To 

ensure its safe operation, additional emergency refuge pull-outs are spaced approximately every 

1600 feet (0.31 miles) with emergency call boxes (Figure 5). Temporary shoulder use is almost 

universally deployed in conjunction with speed harmonization. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 13 

March 2010 

Benefits Assessment 

In the Netherlands, implementing 

temporary shoulder use has had an overall 

capacity increase of seven to 22 percent by 

decreasing trip travel times from one to 

three minutes and increasing traffic 

volumes through the area up to seven 

percent during congested periods (Taale, 

2006). In Germany, this technique has 

demonstrated a 20 percent increase in rushhour capacity and reduced air and sound 

pollution along Munich area freeways 

(translated from “Europe on Course—

Telematics on German Roads” German 

Ministry for Transportation, Construction 

and Housing 2005). 

As described in the Scan Report (Mirshahi 

et al., 2007), temporary addition of a 

shoulder lane allows congested roadways 

to have higher throughput at reduced 

speeds, as indicated in Figure 6. However, 

the key to hard shoulder running is that the 

segment must extend through the roadway 

bottleneck. If it does not extend beyond the 

bottleneck, traffic is simply fed at a greater 

rate into the segment that is already over 

capacity, thereby compounding the 

congestion. 

Source: UK Highways Agency 

Figure 4. Hard Shoulder Running When 

Active and Inactive 

Source: Mirshahi, et al., 2007 

Figure 5. Emergency Pull-Outs Associated with Hard Shoulder Running 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 14 

March 2010 

Operations 

In the UK the Highways 

Agency currently activates their 

speed harmonization system 

whenever hard shoulder running 

is in effect. The addition of the 

shoulder as a travel lane tends 

to increase speeds on 

neighboring lanes due to the 

sudden reduction in traffic 

density. There is some debate 

about whether or not there 

needs to be a limit imposed on 

the speeds during shoulder 

operating periods. Nonetheless, 

a conservative approach may be 

prudent for the initial 

implementation until postimplementation studies can be performed and analyzed. 

The hard shoulder running implementation in the UK currently only extends between major 

freeway interchanges (or junctions, as they are called in the UK). There is consideration 

underway of extending hard shoulder running through junctions where right-of-way and other 

considerations allow, but this approach has not yet been implemented. The initial plan calls for 

these through-junction lanes to be permanently open, as opposed to dynamic opening and closure 

as in traditional hard shoulder running (UK Highways Agency, 2008). 

Safety and Design Considerations 

Safety is generally the greatest concern when implementing shoulder-running strategies, since 

use of the roadway outside shoulder as a travel lane results in the loss of a continuous emergency 

refuge area for disabled vehicles and during incidents. Depending on the length of the hard 

shoulder running section, European examples suggest that the provision of infrequent paved 

emergency refuge areas or pull-outs should be considered during analysis and design of the 

affected segment. Alternative refuge areas would be outside of the shoulder area and would 

provide a designated place for stalled or disabled vehicles while allowing use of the hard 

shoulder as a travel lane (Figure 5). In England, the alternative refuge areas are spaced every 

one-third or one-fourth mile. Alternatively, Germany does not generally include refuge areas. 

Very short segments may not require a refuge area. 

Pavement markings for the hard shoulder vary by installation and country as well. In Germany, 

the outside edge is not striped, which makes the lane appear more like a shoulder. However, in 

the Netherlands, the outside edge has a solid stripe, except in the emergency refuge area 

locations where it is dashed. This makes the shoulder appear more like a travel lane. Dynamic 

lane markings such as lighted pavement markers could be used to assist in delineating the travel 

lanes for motorists, especially for dynamic changes in ramp exits as shown in Figure 7. 

Source: Lemke and Irzik, 2006) 

Figure 6. Speed-Volume Relationship of Temporary 

Shoulder Use 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 15 

March 2010 

Another safety issue relates to 

impediments in the shoulder 

(i.e., stalled vehicles or other 

debris) that needs to be cleared 

before opening the lane to use. 

The English approach requires a 

visual inspection of the shoulder 

before it is opened. This 

requires some intervention on 

the part of operators, which 

means that the system cannot be 

automatically engaged. 

Verification that the lane is 

clear of obstacles is completed 

via CCTV cameras for the M42 

motorway system and for 

shoulder operation in Germany. 

Clearly, this requires strategic 

camera placement to ensure the 

affected shoulder is clear and 

can be opened for hard shoulder running. 

In Germany, the Netherlands, and the UK, temporary shoulder use is typically implemented in 

conjunction with speed harmonization. In the Netherlands, additional traffic management and 

ITS treatments are used along with hard shoulder running to help mitigate any adverse safety 

consequences. These include (Helleman, 2006): 

• Overhead lane signs; 

• Emergency refuge areas with automatic vehicle detection (in-pavement loop detectors); 

• Speed reduction during times of temporary shoulder use; 

• Variable route signs at junctions; 

• Advanced incident detection; 

• CCTV surveillance; 

• Incident management; and 

• Roadway illumination. 

3.5 Junction Control 

A method to dynamically change lane allocation at an interchange is called Junction Control. It 

can be used at freeway off-ramps or on-ramps (Figure 7 and Figure 8); particularly for high 

volume ramps often associated with major freeway-to-freeway interchanges. The rationale for 

use is that in some traffic conditions or at certain times of day, it may be more effective to use 

existing downstream or upstream lanes for one type of movement or for traffic coming from the 

main lanes while at other times of day it may be more effective to use the through lanes for the 

ramp movement. For example, when ramp volumes are relatively light or mainline volumes are 

very heavy, it might be most effective to have an entrance ramp merge into the right lane. 

However, there may be times that the volume on the ramp is extremely high while the mainline 

volumes are low. In this case, traffic merging from the on-ramp will have to find gaps in the 

Source: The Netherlands 

Figure 7. Junction Control at an Exit with Hard 

Shoulder Running 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 16 

March 2010 

mainline traffic, despite the 

mainline traffic being relatively 

light. The delay caused by 

hesitation and time required to 

find a gap may be disruptive to 

ramp capacities and flows and 

thus, create a situation with 

higher rear-end collision 

potential on the ramp. Junction 

control is used to “close” the 

right lane of the mainline 

upstream of the ramp through 

the use of lane control signs in 

order to give ramp traffic a near 

free-flow onto the mainline. 

Junction control provides 

priority to the facility with the 

higher volume and gives a lane 

drop to the lesser volume 

roadway. 

Junction control can also be used at off-ramps, especially when hard shoulder running is used, to 

dynamically create a two lane off-ramp with a freeway drop lane and an option lane. Junction 

control is only advantageous at on-ramps when the mainline has spare capacity (giving priority 

to a higher merge volume). Similarly, junction control at an off-ramp is only desirable if an exit 

ramp has available width to accommodate an additional exit lane (giving priority to a higher 

exiting volume and/or downstream merging volume). 

Benefits Assessment 

In the Netherlands, a pilot junction control project at the Diemen interchange resulted in a 

reduction of overall mean travel times of seven and eight percent and reduced vehicle delay of 

four and 13 percent for both mainline and merging traffic, respectively (Helleman, 2006). 

Operations 

Junction control has been applied in Germany, typically at merge points or entrance ramps where 

there are a lower number of travel lanes downstream of the merge point. This requires the 

installation of lane control signals over the upstream and merging travel lanes, dynamically 

providing priority to the facility with the higher volume (Tignor, et al., 1999). The noted 

examples do not typically employ dynamic lane markings to match the changed merge 

conditions communicated by overhead signs, although this dual approach has been applied in the 

Netherlands. 

3.6 Dynamic Re-routing 

Dynamic re-routing involves directing motorists to take an alternate controlled access route 

within a regional freeway network, using either full-matrix dynamic message signs or rotational 

prism guide signs. The signs change with traffic conditions to provide information regarding 

queues, major incidents, and alternate routes. 

Source: Germany 

Figure 8. Junction Control On-Ramp Schematic 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 17 

March 2010 

In Germany, the use of dynamic 

re-routing information is a 

critical component of their 

ability to meet their national 

goal, which is to serve 80 

percent of all trips on the 

motorway network using realtime traffic and traveler 

information by 2010. In the 

Netherlands, dynamic route 

information has been provided 

since 1990, currently utilizing 

over 100 gantries to display 

informational panels across the 

country on major motorways. 

Figure 9 shows a dynamic route 

sign in the Netherlands 

(Middelham, 2006). 

A hybrid sign can also be used for dynamic re-routing. A static sign comprises the major portion 

of the sign, but the route shields and destinations are changeable within the fixed sign panel, such 

that they can direct motorists to take the alternate route. These hybrid signs are typically located 

over the affected lanes approaching an interchange. For the normal “through” route, the shields 

and destinations are deactivated (changing the shield and destination part of the panel to 

background blue or in the case of US implementation, green) or displaying route closure 

notification in the same space. Meanwhile, the exit or diverging ramp sign includes the alternate 

route shield with downstream destinations. Algorithms are applied to properly display the route 

diversion on all affected downstream signs, and can be automated or manually activated from a 

traffic control center. Dynamic re-routing typically addresses only the most prominent or 

strategic routes within a freeway network. Dynamic re-routing may also be employed with 

junction control to help manage traffic in a variety of contexts. For example, if junction control is 

used to provide additional exit lanes and reduce through lanes at a particular junction, dynamic 

re-routing could be used to divert through traffic to parallel routes. Similarly, junction control 

can also support dynamic re-routing by providing additional capacity to a particular movement 

that has been targeted for re-routing. 

Benefits Assessment 

The ability of this technique to divert up to 40 percent of through-traveling vehicles was shown 

on Nuremberg area freeways in Germany, leading to reduced travel times and emissions 

(translated from “Europe on Course—Telematics on German Roads” German Ministry for 

Transportation, Construction and Housing 2005). The Dutch have estimated a five percent 

improvement in overall system performance associated with dynamic re-routing (Middelham, 

2006). 

Compliance 

The driver compliance rate increased on German freeways when a reason for the re-routing was 

given in addition to the alternate route information (translated from “Europe on Course—

Source: Middleham, 2006 

Figure 9. Dynamic Route Information in The 

Netherlands 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 18 

March 2010 

Telematics on German Roads” German Ministry for Transportation, Construction and Housing 

2005). Assessment studies completed by the Dutch indicate that between eight and 10 percent of 

drivers comply with the changed route information (Middelham, 2006). 

3.7 Traveler Information 

The Germans, Danes, and Dutch successfully employ traveler information to increase roadway 

efficiency and performance. In Germany, the traffic management centers (TMC) serve a critical 

role in disseminating information to roadway users about incidents, congested conditions, and 

other events or situations that may impact operations. The TMCs use the traffic data to change 

speed, lane usage, and route guidance information. One of the methods of informing drivers is to 

use rotational prism guide signs that change with traffic conditions. 

In Denmark, the Traffic Information Center (TIC) was established in 1982 in a joint effort with a 

private company to provide traffic reports on morning radio news programs. The TIC covers all 

of Denmark and operates 24 hours a day, seven days a week. Traffic-related data is acquired 

from a number of sources, such as law enforcement, counties, municipalities, private citizens, 

private companies, transportation agencies, traffic reporters, road sensors, monitoring cameras, 

and weather stations. The TIC disseminates information in a variety of ways to reach the largest 

number of potential users. 

Benefits Assessment 

Traffic information systems in Germany have proved effective, especially when integrated with 

other traffic management systems (translated from “Europe on Course—Telematics on German 

Roads” German Ministry for Transportation, Construction and Housing 2005). 

3.8 Summary 

There are a number of traffic management techniques that can be applied on a spot basis, a 

roadway basis and on a system-wide basis to positively affect overall roadway and system 

operations. The application of combined set of traffic management techniques at the system-wide 

level is a considerable undertaking, but one that can yield considerable operational benefits and 

system-wide efficiencies. 

All countries discussed in this report have or are implementing or expanding a variety of traffic 

management techniques. However, the UK is perhaps approaching the concept of traffic 

management on a system-wide, multimodal basis most fully by embarking on their managed 

motorways approach, which strives to manage the entire roadway system and other modes 

interfacing with the roadways as efficiently and effectively as possible using multiple 

management strategies. In this sense, the UK is approaching the concept of Integrated Corridor 

Management that has recently been discussed in the US, in which management strategies are 

applied to an entire travel corridor (freeway, ramp systems, transit facilities and parallel arterials) 

to best utilize all transportation facilities, regardless of facility type or jurisdiction, within a 

travel-shed. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 19 

March 2010 

4.0 System Level Applications 

This chapter examines benefits at the corridor and system level, reporting on identified or 

potential synergistic relationships between any of the European- or US-based traffic management 

techniques. System level applications will examine the following contextual settings: 

• Overall roadway management including all access connections to the system; 

• Spot roadway management strategies that function to improve overall flow in the system; 

• Incremental implementation of synergistic applications; and 

• How these systems could be adapted to existing ITS and traffic operations investments 

commonly found on US freeways based on a phased approach. 

4.1 Overall Roadway Management 

The intent of this chapter is to document cases where synergistic relationships between traffic 

management strategies have been found; however, performance monitoring data regarding these 

strategies to date has been limited. Because this data is rarely stratified by strategy, being able to 

use it to estimate an individual strategy’s contribution to system level benefits is even more 

challenging. Nonetheless, research has shown that these strategies are rarely implemented in 

isolation, and a number of them are clearly complementary. While most of these strategies have 

some form of relationship with all of the others, there are some that stand out most clearly as 

complementary and/or supportive to a particular technique. Figure 10 indicates typical 

complementary and/or 

supportive strategies for each of 

the six European traffic 

management techniques. Note 

that while one technique may 

support another, the reverse is 

not always true. For example, 

while speed harmonization may 

be a critical supportive strategy 

for implementing hard shoulder 

running; hard shoulder running 

is not critical to the success of 

speed harmonization 

applications. 

A brief discussion of how these techniques could be applied in a synergistic manner is provided 

below. Not all combinations of complementary and/or supporting techniques are discussed, but 

the write-up provides a general idea of how certain strategies can work together. 

Speed harmonization, for example, is often implemented in tandem with queue warning. Queue 

warning complements speed harmonization because in addition to warning drivers of 

downstream queues, it communicates the reason why speeds are being lowered. In Germany, a 

congestion pictograph or icon is displayed on both sides of the overhead gantries to alert 

motorists of queues or congestion ahead. The value of the system lies in warning drivers of 

downstream queues so they take appropriate actions (e.g., slow down or change lanes), thereby 

reducing the occurrence of primary and secondary collisions caused by the congestion. In the 

Source: Parsons Brinckerhoff, 2009 

Figure 10. Relationships Between ATM Strategies 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 20 

March 2010 

Netherlands, motorists are alerted of queues with flashing lights surrounding the variable speed 

limits, and speed harmonization is activated with variable speed limit signs. 

Queue warning is valuable in that it warns drivers of downstream queues so they take 

appropriate action to slow down or change lanes, reducing the occurrence of primary and 

secondary collisions caused by congestion. Queue warning can be supported by the 

implementation of speed harmonization to further enforce the need to reduce speeds. 

Hard shoulder running is frequently implemented in conjunction with both speed 

harmonization and queue warning, as well as with junction control because they share the 

common need of addressing recurring congestion in bottleneck locations. Limited data from the 

UK indicates how these techniques can build upon each other. Transportation professionals in 

the UK believe that using speed harmonization and queue warning is important in order to 

maintain safety during hard shoulder running operations. Since hard shoulder running removes 

the shoulder for use as a breakdown lane, having a robust incident management program in place 

to monitor and respond to incidents as soon as possible is essential. Where hard shoulder running 

begins or terminates at a ramp junction, junction control is often required to maintain lane 

continuity and safe operations. 

Junction control may be enhanced when supported by ramp metering, particularly when used at 

freeway on-ramps. If the control strategy has changed a junction from an add-lane to a merge 

condition, ramp metering would be especially beneficial to break up platooning vehicles from 

entering a ramp and facilitate the merge condition. Dynamic re-routing can support junction 

control as well in that if the control strategy reduces capacity of one movement (e.g., the through 

movement) in favor of another movement (e.g., the exiting movement), then it may be beneficial 

to re-route some through movement traffic to alternate routes so as to not experience undue 

congestion. 

Dynamic re-routing is highly dependent on traveler information (including queue warning) to 

not only direct drivers to the desired alternative parallel route, but to also inform them as to why 

they are being encouraged to reroute. Information could include projected travel times via 

alternative routes and reasons for the delay on the primary route, e.g., “accident ahead.” Junction 

control can also support dynamic re-routing by providing additional capacity to a particular 

movement that has been targeted for re-routing. 

Ramp metering can be enhanced by queue warning and traveler information when used to 

address mainline congestion. These techniques can provide the driver with information on why 

the ramp meter rate is operating in a given manner, which can lead to more acceptance of the 

meter and higher compliance. 

4.2 Spot Roadway Management Strategies 

In many urban roadway networks, overall system capacity is governed by localized constraints, 

or “bottlenecks,” at a limited number of locations. Addressing these bottlenecks can make a 

significant improvement in overall system performance and reliability. Often times these 

bottlenecks cannot be physically expanded due to either prohibitive costs or environmental 

concerns. These conditions can also be present during construction where detours do not offer 

the capacity, performance or operational safety of the final roadway configuration. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 21 

March 2010 

Because traffic management techniques are generally less expensive than the physical expansion 

of facilities, it can more feasibly be used as a means of addressing these conditions. For example, 

various traffic management strategies have been applied in Denmark as a way of maintaining 

traffic flow during construction 

Hard shoulder running is one of the more effective traffic management techniques that can 

provide additional capacity on an as-needed basis to address bottleneck issues. For hard shoulder 

running to be truly effective, it needs to extend through the bottleneck location upstream of 

typical queues. Otherwise it is simply moving the bottleneck to a new location. 

4.3 Incremental Implementation 

It is important to consider the environment within which potential traffic management techniques 

will be implemented; for example, are ramp metering, service patrols, existing VMS, managed 

lanes, or other more US-based techniques already a part of the freeway management system? 

While these more traditional elements can be integrated into many traffic management 

techniques or strategies, careful consideration should be given to implementing traffic 

management techniques that lend themselves to being actively managed when the more basic 

traffic management systems are not in place. This is particularly relevant when considering the 

overall operation of the system and the demands it may place on existing traffic management 

center facilities and staffing requirements. 

It is important to consider the overall system and plan for the best combination of traffic 

management techniques for the region or area under consideration. Many logical and synergistic 

combinations of techniques lend themselves to incremental implementation that improves 

effectiveness. The benefit of this is that it allows agencies to implement some applications 

sooner rather than later, building users’ experience and trust in the general traffic management 

concept prior to implementation of supporting techniques. Examples of techniques that have 

been implemented incrementally include speed harmonization, followed by hard shoulder 

running in the UK on the M42. Speed harmonization produces clear benefits to safety and 

operations – the inclusion of hard shoulder running in select locations increases the system’s 

ability to decrease congestion and improve overall operations and throughput. The European 

experience is filled with examples where an initial corridor was fully instrumented and 

monitoring demonstrated proven effectiveness before wider system applications occurred. This 

approach also allowed agencies to ‘learn from their mistakes” in refining the applications in 

order to improve performance and lower their investment costs. 

The deployment of traffic management techniques that will be managed actively should be done 

considering logical operating segments within the system under consideration. Logical starting 

and stopping points based on travel patterns, freeway geometrics, observed operations of 

recurrent congestion or persistent queuing, and areas with higher than expected crash rates 

provide insight into areas where initial investigation and consideration of active management 

techniques may be warranted. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 22 

March 2010 

4.4 Adaptation to Existing US ITS and Traffic Operations 

Investments 

Much of the following discussion is based on work conducted by the Washington State 

Department of Transportation. This dialog is illustrative of similar adaptations occurring in other 

states as of 2010. 

Integration with Current ITS Infrastructure 

Current traffic management systems require a variety of instrumentation and communication 

investments to make the system functional. Some of this equipment is multi-purpose serving a 

number of traffic management techniques (e.g., in-road or other forms of vehicle detection, 

CCTV, VMS, communications network/equipment, etc). In many cases new or augmented 

equipment specific to the desired traffic management technique would be required (e.g., variable 

speed limit signs for speed harmonization). If existing equipment, detection, or traffic 

management systems are in place, their functionality should be reviewed to determine if they can 

be used for both the original intent as well as the proposed traffic management technique(s) to 

obtain the greatest benefit from existing system investments. The traffic management system will 

be relying on accurate, reliable and continual input for the various traffic management 

application algorithms – maintaining a high level of reliability on detection is crucial. 

The variable message signs used to support these techniques are similar to sign technology used 

elsewhere by state DOTs. However, the purpose and application of the VMS signs is different 

than what has been typically used, due to the over lane positioning of the speed harmonization 

signs, their size, mounting maintenance and access requirements. Once again, it will be 

important to assess the existing system capabilities, the requirements of the new system, and 

their subsequent integration. For example, some transportation management system software can 

communicate with NTCIP signs, making integration much easier than if proprietary 

communication protocols are used. 

Institutional Issues 

Institutional issues are challenges that can prevent proper implementation of active traffic 

management techniques, but instead of being attributed to technology or engineering, these 

issues are caused by regulatory, legal, financial, management, organizational, human, or physical 

resource concerns and constraints and can even vary by state and locale. 

Institutional issues differ between Europe and the US in various respects. European agencies 

may be subject to less liability due to legal statutes; they are perhaps more attuned to 

experimenting because there is limited funding and few geometric options to widen or otherwise 

add capacity through expansion or new routes; and for many applications they have a longer (and 

successful) track record in active traffic management accepted by their political and public 

stakeholders. 

• Legal statutes and case law may limit US agencies’ interest in such concepts as hard 

shoulder running, since the effective pavement, when not traveled on, is supposed to 

provide a safe refuge for emergency parking. Many European freeways do not 

traditionally have paved shoulders on one or both sides of the mainline lanes. Providing 

‘hard’ shoulders that are able to take all types of vehicle loads as traveled lanes during 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 23 

March 2010 

peak periods improves capacity and mobility while not adversely impacting safety if the 

shoulder is able to be adequately monitored. 

• Transportation policies within the US tend to favor more capital investment in the “hard” 

side road system, while operational investments in some European countries are the 

primary (and in many cases only) form of investment occurring outside maintenance 

needs. The institutional arrangements within Europe reflect both federal and regional 

provinces in the decision making roles, not unlike the federal/state/local relationships in 

the US. 

• The Netherlands countrywide investment in active traffic management, currently 

underway on all motorways, dates back more than 20 years to much earlier 

demonstrations that provided insight into successful deployment under specific 

conditions. Institutionalizing a network approach came from these corridor 

demonstrations. Adjacent countries have now borrowed such experiences and system 

approaches from each other and share common implementation schemes. As noted 

above, within the US most agencies have focused more on rehabilitation and expansion 

projects with less comparative investment in operations. And similar to the European 

experience, just as much downstream time from initial US applications of actively 

managed traffic techniques to widespread adoption may be required. 

Because many of these strategies are relatively new to the US, some institutional issues may 

need to be worked out. Even inter-agency and intra-agency issues can present implementation 

obstacles. The difficulty with institutional issues is that there are no consistent approaches to 

resolve them. Some general institutional issues that can impact implementation of a wide variety 

of actively managed techniques in the US include the following: 

• Priority: for traffic management techniques to operate successfully and reach their full 

potential, the techniques must be given priority for funding, programming and 

maintenance. 

• Continued Funding for Operations and Maintenance: sustained funding is essential to 

operate and maintain a safe and effective traffic management strategy. Operational 

funding provides the necessary staff to monitor, control, and adjust a system. 

Maintenance of a system is also necessary for proper operations, and the threshold for 

maintenance reliability may need to be much higher for passive in-field systems that are 

predicated on public respect to be effective. Any expansion of a traffic management 

system will also require sufficient and ongoing funding. Some delivery strategies, 

including design-build-finance-operate-maintain procurements, have been employed to 

assure the level of maintenance required in European examples. 

• Continued Funding for Electronic Equipment: electronic components used in these 

systems have a shorter life cycle than typical components in highway transportation. A 

program for preservation is needed in addition to an on-going maintenance program. 

• Continuous Staffing for Traffic Management Center Operations: staffing hours at a 

TMC may need to be expanded in order to safely and effectively operate traffic 

management systems in an active manner. A benefit-cost analysis should be undertaken 

to determine if the collision and congestion reduction benefits of implementing a traffic 

management technique will off-set the expected capital and operations and maintenance 

costs. 

• System Monitoring and Evaluation: the use of effective monitoring and data collection 

allows implemented traffic management systems to be evaluated and improved. This 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 24 

March 2010 

would typically coincide with a performance monitoring program with set objectives and 

thresholds in order to effectively determine if the system is meeting its goals. 

• High Quality System Information: providing accurate and reliable information to the 

system is essential for the safe and effective implementation and operation of any 

management technique. This is necessary to earn drivers’ trust and compliance for the 

systems. Accordingly, the algorithms behind the strategies must operate in real-time, with 

abilities for the system to self regulate with minimum operator oversight except to 

confirm specific pre-set actions. 

• Public Education: increasing US driver familiarity with actively managed traffic 

techniques and systems, their purposes, and congested freeway safety requires an 

ongoing public information campaign. 

Speed harmonization and hard-shoulder running may face additional institutional considerations 

in the US, such as the following: 

• Coordination with Enforcement and Emergency Response Agencies: for successful 

operation, the proposed management techniques should be discussed with the 

enforcement/public safety entities (e.g. state patrol) and other key stakeholders such as 

emergency responders. These agencies must understand the overall function of the 

management techniques and collaborate with the operating agency on enforcement 

protocols. Enforcement protocols and understanding are important for the implementation 

of a speed harmonization system due to the variable nature of the speeds over a length of 

roadway; enforcement may want to focus on more obvious or blatant speed violations. 

For hard shoulder running, enforcement must be vigilant due to the safety issues and 

emergency responders must understand how using the shoulder as a travel lane will affect 

their response times. 

• Enforcement Plan for Traffic Management Techniques: without enforcement, some 

of the traffic management techniques and strategies may not be as successful. It is vital 

that appropriate warnings and enforcement actions are taken for motorists who disregard 

the regulatory signing. Enforcement may add a cost component to implementation and 

operation. Public outreach efforts must work to reinforce the strategies and help foster 

public trust in the system. As an example, motorists need to learn that when the signs 

show a reduced speed limit that there is a good reason to slow down. With hard shoulder 

running, it is important that motorists understand when this technique is operational and 

when it is not. As such, appropriate warnings and actions must be taken for those who are 

not compliant. 

Suggestions to Address Institutional Issues 

Reaching solutions to a range of institutional issues, which allows for the successful 

implementation of a variety of traffic management techniques and systems, requires 

collaborative planning and development. To effectively implement traffic management 

techniques that are actively managed in the US the following actions are suggested (WSDOT 

ATM Concept of Operations Report, 2008): 

• Provide Continuous Operations: providing continuous hours of operations of most 

techniques that will be actively managed is recommended, especially for speed 

harmonization and queue warning. This will provide necessary activation and monitoring 

of the system. By operating the system any time it is needed, stakeholder acceptance and 

public trust is created. Additionally, some legal liabilities may be reduced. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 25 

March 2010 

• Outreach to Stakeholders and Public: informing stakeholders and the public regarding 

the purposes, benefits, operation and performance outcomes of traffic management 

strategies will also build trust in the investments. 

• Outreach to Government Officials: continued support of traffic management 

techniques and systems will require early involvement with key officials and 

stakeholders. Various elected and appointed public officials should be informed about the 

techniques and benefits, especially before including these techniques in funded programs 

and project budgets. 

• Coordinate with Law Enforcement and Key Partnering Agencies: law enforcement 

needs to be involved with the design and intended operation of actively managed traffic 

management systems in order to determine how the system can accommodate 

enforcement and how officials should enforce it. Other agencies may also be interested in 

how potential management techniques could affect traffic on their transportation 

networks as well. 

• Create a Concept of Operations Plan: for the purposes of design, outreach, and 

operations, a concept of operations plan will be required to provide clarity into how a 

system will operate. This plan also includes ITS integration and determining operational 

responsibilities. 

• Integrate with ITS Infrastructure: creating and implementing a plan for integration 

with ITS architecture will define the roles of individual traffic management techniques 

and ITS. 

• Improve Analysis and Review: proper monitoring of a operational network and 

comprehensiveness of a network model are beneficial for monitoring techniques and 

predicting the effect of proposed techniques. 

• Obtain Approval for Experimental Traffic Control Devices: as traffic management 

techniques that are dynamically managed are new to the United States and frequently rely 

on signage and control procedures that are not currently described in the MUTCD, steps 

for experimental approval should be taken when a project timeline is set in order to 

ensure approval when the system will be activated. 

• Collaborate with Other States and Partnering Agencies: several locales in the US are 

investigating and implementing the discussed traffic management techniques. Working 

with these states in gaining lessons learned can provide shared insight into how to address 

institutional and engineering issues. 

• Coordinate with TDM Efforts: often times personnel charged with developing TDM 

policy are compartmentalized from operations staff who would be implementing the 

traffic management techniques. Coordinating these and other congestion management 

tools so as to provide a holistic approach is likely to produce more effective results. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 26 

March 2010 

5.0 Initial US-Based Implementation of European 

Traffic Management Strategies 

As of early 2010, a number of US states and locales were moving forward with the study and 

implementation of various traffic management strategies. This list is not exhaustive and includes 

the following: 

5.1 Under Study 

• Colorado DOT is evaluating a speed harmonization system for I-70. 

• Florida DOT is exploring hard shoulder running and variable speed limits on a portion of 

I-75. 

• MTC and California DOT (Caltrans) are considering variable speed limits on I-80 in the 

Bay Area. 

• North Carolina DOT is examining hard shoulder running options along portions of I-77 

and I-485 in the Charlotte area. 

5.2 Implementation 

• California DOT (Caltrans) has implemented in-pavement dynamic lane controls on the 

expanded I-15 managed lanes in San Diego and is implementing dynamic lane operations 

on northbound SR-110 at the I-5 freeway interchange in Los Angeles. 

• Minnesota DOT, as part of their priced dynamic shoulder lane project, is now operating 

variable speed controls and queue warnings in a three-mile segment of I-35W as part of 

their Urban Partnership grant, and an extension of the system is planned. They are 

studying the implementation of a similar approach for portions of I-94 between 

Minneapolis and St. Paul. 

• Texas DOT tested dynamic re-routing and dynamic queue warning using portable solarpowered monitors, signs and cameras as part of a reconstruction of two converging 

interstates in Hillsboro, helping drivers avoid sudden queues. 

• Virginia DOT is implementing a variable speed limit on I-95 to address construction 

related closures associated with the Telegraph Road interchange reconstruction. 

• Washington State DOT is constructing a variable speed limit/queue warning system on 

approximately eight miles of I-5 as it approaches Downtown Seattle in the northbound 

direction. They are also proceeding with the design and construction of a similar system 

on I-90 and SR 520 across Lake Washington as part of their Urban Partnership grant. All 

systems are anticipated to be operational by 2010. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 27 

March 2010 

6.0 References 

Cambridge Systematics, Inc. MnPASS System Study: Executive Summary. Prepared for 

Minnesota Department of Transportation. Cambridge, Massachusetts, 2005. 

Cambridge Systematics, Inc. Twin Cities Ramp Meter Evaluation. Prepared for Minnesota 

Department of Transportation pursuant to Laws 2000: Chapter 479, HF2891. Oakland, 

California, 2001. 

Federal Highway Administration (FHWA) (2007). Active Traffic Management: The Next Step in 

Congestion Management, International Technology Scanning Program, FHWA, Report 

#FHWA-PL-07-012. 

Federal Highway Administration (FHWA). A Guide for HOT Lane Development. FHWA-OP03-009, US Department of Transportation, Washington, D.C., 2003. 

Federal Highway Administration (FHWA). Fact Sheets on Highway Provisions: Use of High 

Occupancy Vehicle (HOV) Lanes, 2005. Accessed online at 

http://www.fhwa.dot.gov/safetealu/factsheets/hov.htm in January 2009. 

Helleman, B. “Hard Shoulder Running (HSR) in the Netherlands.” Ministry of Transport, Public 

Works and Water Management, Directorate-General of Public Works and Water 

Management, AVV Transport Research Centre, Rotterdam, The Netherlands, Presentation to 

PCM Scan Team, June 2006. 

Kary, B. Urban Partnership Agreement, Innovative Choices for Congestion Relief, PowerPoint 

presentation, Minnesota Department of Transportation, 2009. 

Knibbe, Willem Jan Arne Oostveen, Hans Bokma, Daisy Poot-Geers, (2005), A New Incident 

Detection Scheme developed in The Netherlands, AVV - Transport Research Centre, 

Ministry of Transport, Public Works and Water Management, Rotterdam. 

Koohong Chung, Ching-Yao Chan, Kitae Jang, David Ragland, and Yong-Hee Kim, (2007), 

HOV Lane Configurations and Collision Distribution on Freeway Lanes—An Investigation 

of Historical Collision Data in California, Institute of Transportation Studies, UC Berkeley 

Traffic Safety Center, Paper UCB-TSC-TR-007-9, 2007. 

Lemke, K. and M. Irzik. “Temporary Use of Hard Shoulders—Experiences and Economic 

Assessment.” Federal Highway Research Institute, Traffic Planning, Highway Design, and 

Safety Analyses Section, Bergisch Gladbach, Germany, Presentation to PCM Scan Team, 

June 2006. 

Levinson, D., L. Zhang, S. Das, and A. Sheikh. Measuring the Equity and Efficiency of Ramp 

Meters. MN/RC—2004-37, Minnesota Department of Transportation. St. Paul, Minnesota, 

2004. 

ir. H. Luikens and dr.ir. M.Westerman, (2004), Regional Traffic Management in The 

Netherlands, Ministry of Transport, Public Works and Water Management, Transport 

Research Centre AVV, Rotterdam, The Netherlands. 

Middelham, F. “Dynamic Traffic Management.” Ministry of Transport, Public Works and Water 

Management, Directorate-General of Public Works and Water Management, AVV Transport 

Research Centre, Rotterdam, The Netherlands, Presentation to PCM Scan Team, June 2006. 
Synthesis of Active Traffic Management Experiences in Europe and Related Articles 28 

March 2010 

Mirshahi, Mohammad, Jon Obenberger, Charles A. Fuhs, Charles E. Howard, Dr. Raymond A. 

Krammes, Dr. Beverly T. Kuhn, Robin M. Mayhew, Margaret A. Moore, Khani Sahebjam, 

Craig J. Stone, Jessie L. Yung. Active Traffic Management: The Next Step in Congestion 

Management. United States. Federal Highway Administration. Office of International 

Programs. Washington, DC: U.S. Department of Transportation, July 2007. 

Mott MacDonald Ltd. ATM Monitoring and Evaluation 4-Lane Variable Mandatory Speed 

Limits 12 Month Report. Highways Agency, Bristol UK, 2008. 

Pieper, Roel, Jan Prins, et al. (2001), MobiMiles, Introducing an integrated concept for variable 

road pricing, based on time, location and vehicle. Report prepared for the Ministry of 

Transport, Public Works and Water Management, The Hague, The Netherlands. 

Sparmann, J. “Freeway Operation in Germany Experiences in Hessen.” Presentation to 1st

International Symposium on Freeway & Tollway Operations, Athens, Greece, June 2006. 

Stembord, Henri and Huib Kwint, (2005). Country Report of the Netherlands with emphasis on 

Dynamic Lane Marking, Ministry of Transport, Public Works and Water Management, 

Rijkswaterstaat Transport Research Centre (AVV), Rotterdam, The Netherlands. 

Taale, H. “Regional Traffic Management Method and Tool.” Ministry of Transport, Public 

Works and Water Management, Directorate-General of Public Works and Water 

Management, AVV Transport Research Centre, Rotterdam, The Netherlands, Presentation to 

PCM Scan Team, June 2006. 

TTI-FHWA: Texas Transportation Institute and Parsons Brinckerhoff. Development of an Active 

Management Screening Tool: Deliverable 1, Literature Review, Houston, TX, 2008. 

UK Highways Agency Interim Advice Note 87/07, The Provision of Signal Gantries for 

Motorways with Four or More Running Lanes, 2007. 

UK Highways Agency, Managed Motorway Implementation Guidance, Through Junction Hard 

Shoulder Running, 2008. 

UK Department for Transport, Advanced Motorway Signaling and Traffic Management 

Feasibility Study, A Report to the Secretary of State for Transport. UK Department for 

Transport, 2008. 

Washington State Department of Transportation (WSDOT), Active Traffic Management Concept 

of Operations, Parsons Brinckerhoff, Telvent Farradyne, Jacobs Carter Burgess. 2008 

Washington State Department of Transportation (WSDOT), Active Traffic Management 

Conceptual Design Layouts and Cost Estimates, Parsons Brinckerhoff, Telvent Farradyne, 

Jacobs Carter Burgess. 2008 

Washington State Department of Transportation (WSDOT). Design Manual. M 22-01.03, 

Washington State Department of Transportation. Olympia, Washington, 2008. 

Wendelboe, Jens Toft (2008), “When Under Construction: Copenhagen’s Motorway 

Experience”. Traffic Technology International Annual. 

Yibing Wang (1), George Sarros (1), Markos Papageorgiou (1) and Willem Jan Knibbe (2), 

(2005), Real-time Route Guidance in Large-Scale Urban Express Ring-Roads, (1) Dynamic 

Systems and Simulation Laboratory, Technical University of Crete, Greece and (2) 

Rijkswaterstaat AVV, Rotterdam, The Netherlands. 

Translated Document: “Europe on Course—Telematics on German Roads” German Ministry for 

Transportation, Construction, and Housing, 2005 
U.S. Department of Transportation 

Federal Highway Administration 

Office of Operations (HOP) 

Mail Stop: E86-205 

1200 New Jersey Avenue, SE 

Washington, DC 20590 

Web site: http://ops.fhwa.dot.gov

Publication # FHWA-HOP-10-031