TECHBRIEF Safety Evaluation of 

Restricted Crossing U-Turn 

Intersection

FHWA Publication No.: FHWA-HRT-17-083

FHWA Contact: Roya Amjadi, HRDS-20, (202) 493-3383, 

roya.amjadi@dot.gov

This document is a technical summary of the Federal Highway Administration report Development of a Crash Modification Factor for Signalized RCUTs (FHWA-HRT-17-082).

Objective

The Federal Highway Administration (FHWA) established 

the Development of Crash Modification Factors (DCMF) 

program to address highway safety research needs 

for evaluating new and innovative safety strategies 

(improvements) by developing reliable quantitative 

estimates of their effectiveness in reducing crashes. The 

ultimate goal of the DCMF program is to save lives by 

identifying new safety strategies that effectively reduce 

crashes and to promote those strategies for nationwide 

implementation by providing measures of their safety 

effectiveness and benefit–cost (B/C) ratios through 

research. State transportation departments and other 

transportation agencies need objective measures for 

safety effectiveness and B/C ratios before investing in 

new strategies for statewide safety improvements. Forty 

State transportation departments provided technical 

feedback on safety improvements to the DCMF program 

and implemented new safety improvements to facilitate 

evaluations. These States are members of the Evaluation 

of Low-Cost Safety Improvements Pooled Fund Study, 

which functions under the DCMF program.

This research examined the safety impacts of replacing 

a traditional signalized intersection with a signalized 

restricted crossing U-turn intersection (RCUT). An RCUT is 

defined as a three-approach or four-approach intersection 

where minor street left-turn and through movements 

(if any) are rerouted to one-way downstream U-turn 

Research, Development, and 

Technology

Turner-Fairbank Highway 

Research Center

6300 Georgetown Pike

McLean, VA 22101-2296

www.fhwa.dot.gov/research
2

crossovers. The objective was to estimate 

the safety effectiveness of this strategy as 

measured by crash frequency. The primary 

measures examined were based on total 

crashes and fatal and injury crashes. A 

further objective was to conduct a spatial 

patterns analysis, assessing notable clusters 

of crashes, as well as changes to crash 

types and day/night between the before and 

after periods. 

While there are theoretical reasons 

that support the relative safety benefits 

of RCUTs as compared to conventional 

intersections, it is also possible that 

certain RCUT elements could diminish 

or negate these benefits. For example, 

signalized RCUTs involve a greater number 

of signals and require that some users 

travel longer overall distances. There is no 

known completed research on the safety of 

signalized RCUTs. 

Introduction

RCUTs are also known as superstreets, 

J-turns, reduced conflict intersections, 

and synchronized streets. Ten States have 

installed more than 50 RCUTs since the 

late 1980s.(1) At least five States have 

installed signalized RCUTs—those at which 

the major street crossover(s) and U-turn 

crossover(s) are under the control of traffic 

signals. Studies have shown RCUTs to have 

advantages over traditional intersections 

in terms of travel time and delay, signal 

progression, pedestrian crossing, and 

transit service. 

A literature review revealed that few 

research studies have focused on the safety 

effectiveness of RCUTs and none have 

focused on signalized RCUTs. The first of 

three studies analyzing the safety effects of 

RCUTs at unsignalized intersections found 

that at 13 rural sites in North Carolina, stopcontrolled RCUTs replacing two-way stopcontrol intersections led to a reduction in 

total crashes between 27 and 74 percent, 

depending on the analysis method 

employed.(2) The number of fatal and injury, 

angle, and left-turn crashes decreased 

substantially with conversion to the RCUT 

design, while the number of sideswipe, rear 

end, and other crashes decreased slightly 

or increased. The second study, using nine 

sites in Maryland similar to those in North 

Carolina (with the exception of merge 

lanes and yield-control), found a 44-percent 

decrease in total crashes.(3) The third study 

found that stop-controlled RCUTs reduced 

total crashes by 35 percent and injury 

crashes by 54 percent in five rural sites in 

Missouri.(4)

Methodology

This research examined the safety 

impacts of replacing traditional signalized 

intersections with signalized RCUTs. 

The objective was to estimate the safety 

effectiveness of this strategy as measured 

by crash frequency. The primary measures 

examined were based on total crashes and 

fatal and injury crashes. A further objective 

was to conduct a spatial pattern analysis, 

to assess notable clusters of crashes, as 

well as to identify changes to crash types 

and day/night between the before and after 

periods. 

The project team derived a B/C ratio to 

evaluate the overall effectiveness. The 

evaluation of overall effectiveness included 

the consideration of the installation costs 

as well as benefits, characterized as crash 
3

savings (if any) and an estimate of the travel 

time savings experienced by motorists 

using the RCUT.

The project team selected the before-after 

analysis with comparison sites methodology for this evaluation. The method 

accounts for simultaneous event biases, 

which the project team thought to be the 

most threatening potential bias to the 

evaluation. Simultaneous event biases 

that could have been important include the 

recession of the late 2000s and development in the area of the study sites. 

To account for simultaneous event biases, 

the project team used comparison sites as 

described by Hauer.(5) The team identified 

four potential comparison sites for each 

treatment site. Potential comparison sites 

were large surface street intersections (to 

ensure adequate sample sizes) near the 

treatment site (to ensure that the same 

events occurred at both places). Aerial 

photographs were reviewed to ensure 

the sites did not undergo any discernable 

treatment during the study period.

An empirical Bayes methodology was 

unnecessary in this case, because 

regression to the mean was not a serious 

threat to the validity of the analysis. 

The treatment sites were not chosen on 

the basis of any type of hazardous site 

identification process. Instead, the agencies 

selected the sites for RCUT installation 

primarily to relieve congestion. The project 

team collected data from 11 treatment 

sites in 4 States: Alabama, North Carolina, 

Ohio, and Texas. The treatment sites were 

all in suburban areas, on four-lane or sixlane divided arterials, and characterized by 

high-speed traffic and minimal crossing 

pedestrians. 

The full report includes a detailed explanation of the methodology, including a 

description of how the estimate of safety 

effects for target crashes was calculated.

Results

The results for all crashes using comparison 

sites to adjust for potential simultaneous 

event biases are shown in table 1. Eight 

sites had crash modification factor (CMF) 

values less than 1.0, and three sites had CMF 

values greater than 1.0. For nine sites, the 

CMF estimate was more than one standard 

deviation away from 1.0. The group results 

showed CMF values less than 1.0. The 

CMF for all sites was 0.85 with a standard 

deviation of 0.16, so the CMF was less than 

one standard deviation away from 1.0 (i.e., 

the CMF is not statistically significant at the 

95-percent confidence level).

Table 2 shows the results from the analysis 

of injury crashes using comparison sites. 

Note that some of the crash counts for 

groups of comparison sites do not match 

the sums of the component individual sites 

because comparison site data were not 

double counted. The CMF values were much 

like those in the previous table of results, 

with eight sites having CMF values less 

than 1.0 and three sites having CMF values 

greater than 1.0. The CMF for all sites, 0.78, 

was lower than that for all crashes. This 

result suggests signalized RCUTs may have 

a larger positive effect on injury crashes 

than on property damage only crashes. 

The CMF for injury crashes at all sites was 

greater than one standard deviation from a 

value of 1.0.
4

Std. Dev. = standard deviation; AL = Alabama; NC = North Carolina; OH = Ohio; TX = Texas.

Site

BeforePeriod 

Treatment 

Crashes

BeforePeriod 

Comp. 

Crashes

After-Period 

Treatment 

Crashes

After-Period 

Comp. 

Crashes

Var{w} CMF Std. Dev. 

of CMF

AL-Plum 168 228 40 104 0.0055 0.51 0.11

AL-Retail 44 253 3 97 0.0055 0.17 0.10

NC 200 232 159 264 0.075 0.64 0.18

OH-Symmes 113 194 70 78 0.0055 1.49 0.31

OH-Tylersville 104 129 24 50 0.0055 0.57 0.16

OH-HamiltonMason 80 79 9 17 0.02 0.47 0.20

TX-Evans 103 69 325 175 0.0055 1.20 0.23

TX-Stone Oak 42 53 169 168 0.0055 1.20 0.28

TX- New Guibeau 103 158 62 185 0.0055 0.50 0.10

TX- Shaenfield 81 37 82 49 0.0055 0.72 0.19

TX-71 156 93 16 23 0.0055 0.39 0.13

All AL 212 481 43 201 0.029 0.44 0.11

All OH 297 396 103 199 0.0055 0.98 0.16

All TX 485 410 654 600 0.022 0.88 0.15

AL, NC, and OH 709 1,109 305 664 0.011 0.71 0.09

All 1,194 1,519 959 1,264 0.036 0.85 0.16

Table 1. Results from comparison site analysis of each site and groups of sites.
5

Std. Dev. = standard deviation; AL = Alabama; NC = North Carolina; OH = Ohio; TX = Texas.

Site

BeforePeriod 

Treatment 

Crashes

BeforePeriod 

Comp. 

Crashes

After-Period 

Treatment 

Crashes

After-Period 

Comp. 

Crashes

Var{w} CMF Std. Dev. 

of CMF

AL-Plum 25 28 6 13 0.0055 0.45 0.22

AL-Retail 8 15 1 6 0.0055 0.23 0.20

NC 91 39 33 32 0.0055 0.41 0.12

OH-Symmes 48 28 31 8 0.0055 1.90 0.75

OH-Tylersville 35 83 9 32 0.0055 0.62 0.25

OH-HamiltonMason 22 58 3 32 0.0055 0.22 0.13

TX-Evans 29 21 116 60 0.0055 1.27 0.39

TX-Stone Oak 17 20 61 56 0.0055 1.13 0.39

TX- New Guibeau 40 31 17 32 0.0055 0.38 0.13

TX- Shaenfield 27 16 27 28 0.0055 0.50 0.19

TX-71 71 18 11 7 0.0055 0.33 0.15

All AL 33 28 7 13 0.0055 0.41 0.19

All OH 105 169 43 72 0.0055 1.06 0.25

All TX 184 106 232 183 0.0055 0.88 0.15

AL, NC, and OH 229 236 83 117 0.0055 0.63 0.11

All 413 357 315 306 0.068 0.78 0.20

Table 2. Results from comparison site analysis of sites and groups of sites for injury crashes.

Spatial Patterns

The crash data obtained for this evaluation 

specified location well enough to allow for 

a spatial patterns analysis. Notable clusters 

of crashes included the following:

• AL-Plum: Clusters of rear-end crashes 

southbound on the major street.

• NC: Large clusters of rear-end crashes 

in both directions of the major street.

• OH-Symmes: A cluster of rear-end 

crashes northbound on the major 

street and a cluster of rear-end crashes 

eastbound on the minor street.

• OH-Tylersville: Smaller clusters of rearend and sideswipe crashes in both 

directions on the major street.

• TX-Evans: Large clusters of rear-end 

crashes in both directions of the major 

street; a cluster of sideswipe crashes 

northbound on the major street; and a 

cluster of crashes involving northbound 

left-turn vehicles.

• TX-Stone Oak: Large clusters of 

rear-end crashes on the major street 

southbound.

• TX-New Guibeau: Clusters of rearend crashes northbound on the major 

street, on the side with the stem of the 

T-intersection.

• TX-Shaenfield site: Clusters of rear-end 

crashes in both directions on the major 

street; notable clusters of sideswipe 

and fixed object crashes southbound 
6

on the major street on the side with the 

stem of the T-intersection.

Thus, with a few exceptions, the crash data 

mostly showed clusters of rear-end crashes 

occurring at the RCUT sites. These patterns 

are somewhat different from those seen at 

typical conventional intersections, which 

would tend to feature more prominent 

clusters of turning and angle crashes.

Other Variables

The collected data allowed for examination 

of other variables besides severity and 

location. Several important changes 

occurred at sites between the before and 

after periods, including the following:

• AL-Plum: The crash type changed 

drastically, from 68.5 percent “right 

rear angle” crashes in the before period 

to 52.5 percent “rear-end center” in the 

after period.

• AL-Plum: The percentage of daylight 

crashes decreased from 74.4 to 60.

• AL-Plum: The percentage of crashes in 

the rain decreased from 20.2 to 7.5.

• NC: The percentage of “left-turn, same 

roadway” crashes decreased from 29 

to 10.7.

• OH-Symmes: The percentage of fixedobject crashes increased from 0 to 10.

• OH-Symmes: The percentage of wet 

crashes increased from 32.7 to 45.7.

• OH-Tylersville: The percentage of angle 

crashes decreased from 15.4 to 4.2.

• OH-Tylersville: The percentage of wet 

crashes decreased from 26 to 12.5.

• TX-Evans: The percentage of “same 

direction, both going straight, rearend” crashes increased from 11.7 to 22.8.

• TX-Evans: The percentage of “dark, no 

light” crashes decreased from 15.5 to 4.9.

• TX-New Guibeau: The percentage of 

“same direction, both going straight, 

sideswipe” crashes increased from 2.9 

to 16.1, while the percentage of “same 

direction, one straight, one stopped” 

crashes decreased from 57.3 to 38.7.

• TX-Shaenfield: The percentage of 

“same direction, both going straight, 

sideswipe” crashes increased from 2.5 

to 19.5, while the percentage of “same 

direction, one straight, one stopped” 

crashes decreased from 60.5 to 24.4.

• TX-Shaenfield: The percentage of 

“dark, lighted” crashes increased from 

13.6 to 29.3.

The most prominent changes with RCUT 

installation appear to be decreases in angle 

crashes and increases in sideswipe crashes.

Economic Analysis

For the purposes of the economic analysis, 

the assumed treatment is the installation 

of a signalized RCUT. The property damage 

only crash CMF was 0.85, equivalent 

to the total crash CMF in table 1. The 

injury and fatal crash CMF was 0.78, per 

table 2. The costs included construction of 

the RCUT and maintenance of the extra 

traffic signals required by the RCUT. The 

project team obtained installation costs 

for 9 of the 11 installation sites, which 

resulted in an average $354,000 annualized 

construction cost. When added to the annual 

maintenance cost for three extra signals 

at $15,000, this yielded a total annualized 

RCUT cost of $369,000. The service life is 

20 years for RCUTs, like other intersection 

improvements.(6)

Benefits included fewer crashes and shorter 

travel times. The project team assumed
7

the following for computing operational 

benefits:

• On average, the RCUT major street

carries 52,000 vehicles per day.

• On average, the RCUT minor street

carries 10,000 vehicles per day.

• There is no traffic growth during the 

analysis period.

• Thirty percent of daily traffic occurs 

during the four peak hours of the day.

• The RCUT saves 20 seconds per vehicle 

during the 4 peak hours of the day and 

has no net operational effect at other 

times of the day, in line with previous 

estimates of the effects of signalized 

RCUTs.(1)

• Time savings are valued at $15 per 

hour, in line with typical economic 

analyses.

• There are 250 working days per year 

that experience time savings.

The project team assumed the following 

costs for computing the safety-based 

benefits:

• The property damage only crash cost 

in 2014 was $18,000.(7,8)

• The injury and fatal crash cost in 2014 

was $384,000.(7,8)

For benefits, using several of the 

assumptions above, the project team 

estimated the operations to save 103 hours

of motorist time per work day, which 

equates to $388,000 per year. The safety 

benefit was a savings of 3.0 propertydamage-only crashes per year and 2.3 

injury and fatal crashes per year, which 

results in an annual monetary savings of 

$948,000. 

The B/C ratio was 2.6:1 considering the 

safety benefits only and 3.6:1 considering 

the safety and operational benefits. With 

the U.S. Department of Transportation 

recommended sensitivity analysis, this 

value could range from 1.5:1 to 3.6:1 

considering the safety benefits only and 

2.5:1 to 4.7:1 considering safety and 

operational benefits.(8) 

Summary and Conclusions

The objective of this study was to undertake 

a rigorous before–after evaluation of the 

safety effectiveness, as measured by 

crash frequency, of signalized RCUTs. For 

most individual sites and groups of sites 

examined, odds ratio tests showed there 

were high-quality comparison sites 

available, which enhanced the strength 

of the analyses. Therefore, this evaluation 

determined the following as the best 

general estimates of CMFs (and their 

corresponding crash reduction factors 

(CRFs)) for conversion of a conventional 

intersection to an RCUT intersection:

• Overall crashes: CMF = 0.85 

(CRF = 15 percent).

• Injury crashes: CMF = 0.78 

(CRF = 22 percent).

The standard deviations of the CMFs were 

0.16 and 0.20, respectively. This indicates that 

the CMF for overall crashes was not significantly different from a neutral value of 1.0. 

At the individual site level of analysis, 8 of 

the 11 sites showed decreases in overall and 

injury crashes after RCUT installation. The 

three sites with increases (OH-Symmes, 

TX-Evans, and TX-Stone Oak) were the only 

treatment sites with three lanes on both 

minor street approaches. The only other 

treatment sites with three lanes on minor 

street approaches were TX-Shaenfield, a 

T-intersection, and the other two Ohio 

sites with three lanes on one minor street 
8

NOVEMBER 2017 FHWA-HRT-17-083

HRDS-20/11-17(200)E

Researchers—Joseph E. Hummer and Sathish Rao.

Distribution—This TechBrief is being distributed according to a standard distribution. Direct 

distribution is being made to the Divisions and Resource Center.

Availability—This TechBrief may be obtained from the FHWA Product Distribution Center by 

email to report.center@dot.gov, fax to (814) 239-2156, phone to (814) 239-1160, or online at 

http://www.fhwa.dot.gov/research.

Key Words—RCUT, Restricted-Crossing U-Turn, Superstreet, J-Turn, Synchronized Street, 

Signalized, Safety, CMF.

Notice—This document is disseminated under the sponsorship of the U.S. Department of 

Transportation (USDOT) in the interest of information exchange. The U.S. Government assumes 

no liability for the use of the information contained in this document. The U.S. Government 

does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in 

this report only because they are considered essential to the objective of the document.

Quality Assurance Statement—The Federal Highway Administration (FHWA) provides highquality information to serve the Government, industry, and public in a manner that promotes 

public understanding. Standards and policies are used to ensure and maximize the quality, 

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References

1. Hummer, J.E., Ray, B., Daleiden, A., Jenior, 

P., and Knudsen, J. (2014). Restricted 

Crossing U-Turn Intersection Informational 

Guide, Report No. FHWA-SA-14-070, Federal 

Highway Administration, Washington, DC.

2. Hummer, J., Haley, R., Ott, S., Foyle, R., 

and Cunningham, C. (2010). Superstreet 

Benefits and Capacities, Report No. FHWA/ 

NC/2009-06, North Carolina Department of 

Transportation, Raleigh, NC.

3. Inman, V. and Haas, R. (2012). Field 

Evaluation of a Restricted Crossing U-turn 

Intersection, Final Report, Report No. FHWAHRT-11-067, Federal Highway Administration, 

Washington, DC.

4. Edara, P., Sun, C., and Breslow, S. (2013). 

Evaluation of J-turn Intersection Design 

Performance in Missouri, Report No. 

25-1121-0003-179, Research and Innovative 

Technology Administration, Washington, DC.

5. Hauer, E. (1997). Observational Before-After 

Studies in Road Safety, Pergamon Press 

Oxford, England, UK.

6. Donnell, E. (2014). Development of a CMF 

for Continuous Green T Intersections, Report 

No. FHWA-HRT-16-036, Federal Highway 

Administration, Washington, DC.

7. Council, F., Zaloshnja, E., Miller, T., and 

Persaud, B. (2005). Crash Cost Estimates by 

Maximum Police-Reported Injury Severity 

Within Selected Crash Geometries, Report 

No. FHWA-HRT05-051, Federal Highway 

Administration, Washington, DC.

8. USDOT. (2014). Guidance on Treatment of 

the Value of a Statistical Life (VSL) in U.S. 

Department of Transportation Analyses–2014 

adjustment, Memorandum, U.S. Department 

of Transportation, Washington, DC. Available 

online: http://www.dot.gov/ sites/dot.gov/

files/docs/VSL_Guidance_2014. pdf, last 

accessed July 24, 2017. 

approach and two lanes on the other minor 

street approach. Therefore, it is likely that 

signalized RCUTs may be relatively safer 

when the minor streets are narrower and/or 

carry lower traffic volumes.

There were clusters of rear-end crashes 

on the major streets of the RCUTs. An 

examination of crash types before and 

after RCUT installation showed there was 

generally a conversion from angle crashes 

to sideswipe crashes. 

The evaluation also produced an estimated 

B/C ratio for installing an RCUT at the set 

of test intersections of 3.6 to 1.0 when 

considering safety and operations, or 

2.6 to 1.0 considering safety only. When 

examining the sensitivity of this result 

to changes in crash costs, the B/C ratio 

always exceeded 1.0. Installing signalized 

RCUT intersections at locations similar 

to those studied should generally lead to 

positive results in terms of expected crash 

reductions.