# Presentation: 667857

## Road Weather Information Systems

**Chicago Metro APWA Snow & Ice Control**
**Road Weather Information Systems**
**October 20, 2004**

## Road Weather Information Systems

** ****Weather Impact **
** ****Introduction **(terms, definitions...)
** ****RWIS**
** ****Applications & Resources**

**Road Weather Information Systems**

**Chicago Metro APWA Snow & Ice Control**

## Weather

*Weather*

**Affects transportation outcomes of:**

** ****Safety**
** ****Efficiency**
** ****Cost**

- Weather Impact

## Impacts of Weather on Highway Safety

**Impacts of Weather on Highway Safety**

- 60 vehicle crash on I-94
- in snow. 1 Dead. 2/7/03

- 130 vehicle crash on
- I-95 in snow. 2 Dead
- 2/22/01

- 73 vehicle crash on I-68
- in fog. 2 Dead. 100 Injured
- 5/24/03

- 38 vehicle crash on I-43 in fog. 10 Dead. 2/11/02

- 194 vehicle crash on
- I-710 in fog. 41 Injured.
- 11/04/02

- 66 vehicle crash on I-15 in fog. 24 Injured. 4/01/04

- 70 vehicle crash on I-5 in
- heavy rain. Several Injured
- 1/30/04

- Weather Impact

## Every Year in the United States...

**Nearly 7,000 fatal highway crashes and over 450,000 injury crashes occur annually**
**$2.5 billion is spent annually for snow and ice control**
**About $5 billion is spent on weather related infrastructure damage**
**Billions of dollars are lost in delay and disruption to trips and production**

- ...because of weather

- Weather Impact

## A $2.5 billion/year activity of state and local highway authorities

Involves
stocking of materials
purchase of equipment
scheduling of crews
dispatching for pretreatment, snow/ice removal and salting/sanding

Maintenance operators use weather information of several kinds and scales -- from long range forecasts to data from roadside sensors

**Involves**
- stocking of materials
- purchase of equipment
- scheduling of crews
- dispatching for pretreatment, snow/ice removal and salting/sanding
**Maintenance operators use weather information of several kinds and scales -- from long range forecasts to data from roadside sensors**

**Winter Maintenance**

- Weather Impact

## Impacts of Weather on Mobility

**Other recurring**

**Work Zones**

**Other non-recurring**
**e.g. special events**

**Poor signal timing**

**Incidents **
**(crashes, disabled vehicles)**

**Impacts of Weather on Mobility**

**Travel delay can increase by 11% to 50% depending on weather severity**

**Weather**
**(snow, ice, fog)**

- Weather Impact

- 		       list of common acronyms
- 			_CDU_       Control Data Unit
- 			_CPU_        Central Processing Unit.
- 			_ESS_   	     Environmental Sensor Station
- 			_ITS_   	     Intelligent Transportation Systems
- 			_NTCIP_   National Transportation
-                                          Communications for ITS Protocols
- 			_NWS_      National Weather Service
- 			_RAS_  	     Remote Access Server.
- 			_RPU_  	     Remote Processing Unit.
- 			_RWIS_     Roadway Weather Information System.

- Introduction (terms & definitions)

**Synoptic Weather **
**Forecast**
**12+ hrs**

**Meso-Weather **
**Forecast**
**1-12 hrs**

**Observations**
**and Reports**
**0-1 hrs**

## Weather models

- Road-weather models

- Navier-Stokes equations:

| D   | +   · v = 0,  |   |
| --- | --- | --- |
| -----  |  |  |
| Dt   |  |  |

| Dv   | = - p +  · T* +  f,  |   |
| --- | --- | --- |
|  -----  |  |  |
| Dt   |  |  |

| De    | = - p · v +  -  · q +  r.  |  |
| --- | --- | --- |
|  -----   |  |  |
| Dt    |  |  |

-  over a three-dimensional domain forward in time

-  complex physics and mathematical frameworks

-  models are global, nationwide or local (mesoscale) in scope

-  atmospheric structure and the lower boundary of the atmosphere (land and water)

-  algorithmic solutions to site-specific road conditions

-  inputs provided by the 'weather models'

-  accumulated historical weather for a given locale, typically an RWIS ESS

- Introduction (terms & definitions)

## Environmental Sensor Station

- one or more sensors

- atmospheric, pavement, soil and/or water level conditions

- data collected in the field is stored on site in a Remote Processing Unit (RPU) located in a cabinet

- RPU transmits environmental data to a central location via a communication system

- Environmental data may be used to activate roadway devices, provide decision support to managers, furnish the public with traveler information, and enhance forecasts.

- Introduction (terms & definitions)

## Types of Data Collected and Reported

|  Air temperature |  Pavement temperature |
| --- | --- |
|  Surface condition |  Chemical presence in roadway
 |
|  Visibility |  Precipitation: amount, rate, type 
 |
|  Humidity |  Wind speed and direction |
|  Dew point |  Subsurface temperature |
|  |  |

- 4-7

- Introduction

**Types of Data Collected and Reported**

## Atmospheric Data Definitions 

| Data Type  | Abbr.  | Definition  |
| --- | --- | --- |
| Air Temperature  | Temp  | Air temperature at the RPU.  |
| Dew Point Temperature  | Dew  | Temperature at which the air becomes saturated as it cools. If the road or runway temperature drops to or below the dew point, moisture may develop on the surface. The form the moisture takes depends on the surface temperature and the amount of chemical present.  |

| Relative Humidity  | RH  | Percent of moisture in the air. A relative humidity of 0% shows that the air contains no moisture and 100% shows that the air is completely saturated and cannot absorb more moisture.  |
| --- | --- | --- |
| Wind Speed  | SpdAvg  | Average speed of the wind during a one minute period.  |

**Atmospheric Data Definitions**

- Introduction (terms & definitions)

## Atmospheric Data Definitions continued... 

| Wind Direction  | DirAvg  |  |
| --- | --- | --- |

| Average wind direction during a one minute period. Wind direction can be displayed in two formats: cardinal points or degrees. Cardinal format has 8 possible headings. Degree format displays wind direction in values ranging from 001 to 360.  |
| --- |
|  |

| Direction  | Cardinal Format  | Degree Range  |
| --- | --- | --- |
| North  | N  | 338 - 22  |
| Northeast  | NE  | 23 - 68  |
| East  | E  | 69 - 112  |
| Southeast  | SE  | 113 - 158  |
| South  | S  | 159 - 202  |
| Southwest  | SW  | 203 - 248  |
| West  | W  | 249 - 292  |
| Northwest  | NW  | 293 - 337  |

| Data Type  | Abbr  | Definition  |
| --- | --- | --- |

**Atmospheric Data Definitions**** **continued...

- Introduction (terms & definitions)

## Atmospheric Data Definitions continued... 

| Gust  | SpdGst  | Maximum wind speed measured during a one minute period. The RPU averages the wind speed every four seconds and collects 15 four-second averages in one minute. The largest of these 15 values is the gust value.  |
| --- | --- | --- |
| Precipitation Type  | Precip  | Type of precipitation detected by a precipitation sensor, if one is available. Certain types of precipitation sensors can only detect the presence or absence of precipitation and will display Yes or No. Other types of precipitation sensors, such as the Weather Identifier and Visibility Sensor (WIVIS) or Optical Weather Identifier (OWI), can classify the type of precipitation and will report a specific type of precipitation. The WIVIS and OWI precipitation sensors may report Yes at the onset of precipitation until sufficient time has elapsed to classify the precipitation type.  |
| Precipitation Rate  | Rate  | Average precipitation rate computed every minute. Snowfall is converted to water equivalent and the rate represents the rate of liquid equivalent.  |

**Atmospheric Data Definitions**** **continued...

| Data Type  | Abbr  | Definition  |
| --- | --- | --- |

- Introduction (terms & definitions)

## Atmospheric Data Definitions continued... 

**Atmospheric Data Definitions**** **continued...

| Precipitation Intensity  | Intens  | Intensity of the precipitation as derived from the precipitation rate. The National Weather Service defines the following intensity classes: light, moderate, or heavy.  |
| --- | --- | --- |
| Precipitation Accumulation  | Accum  | Rainfall amount or snowfall liquid equivalent for the period from midnight GMT to the current time. Every 30 seconds the RPU computes the amount of water that accumulated during the previous 30 seconds based upon the precipitation rate. The RPU adds that amount to the previous total accumulation, keeping a running total. At midnight GMT the total accumulation is stored in the history file and the counter is reset to zero.  |
| Visibility  | Vis  | Average distance that you can see, both day and night, computed every three minutes.  |

| Data Type  | Abbr  | Definition  |
| --- | --- | --- |

- Introduction (terms & definitions)

## The use of weather sensors placed strategically along a roadway or on vehicles to provide near real-time data of road weather and pavement temperature conditions, combined with tailored weather and pavement condition information, to provide road maintenance personal and the general public with a decision tool for snow and ice control and route planning.

- What are Road Weather Information Systems (RWIS)?

- RWIS

## 
Environmental Sensor Stations

Processing Systems

Forecasts and Models

Dissemination

**Environmental Sensor Stations**
**Processing Systems**
**Forecasts and Models**
**Dissemination**

**Components of RWIS**

- 4-5

- RWIS

## 1970s: Devices first tested on bridges

1980s: Then introduced to the general highway environment

Today: Now refers to a whole spectrum of data resources

- 1980s:** Then introduced to the general highway environment**
- Today:** Now refers to a whole spectrum of data resources**

**RWIS: from the 1970s to today**

- 4-4

- RWIS

## RWIS Improvements...

**RWIS Improvements****...**

** ****New sensor technologies**
** ****New sensor siting guidelines**
** ****New NTCIP**** Environmental Sensor Station Standards**
** ****Improved ****NWS feeds and data sharing**
** ****Better ****road condition models**
** ****Open systems development**** for information exchange**
** ****Data fusion**** of multiple data sources and scales**

## Typical WEATHER STATION COMPONENTS

**Typical WEATHER STATION COMPONENTS**

- RWIS

## RWIS SENSORS- ATMOSPHERIC -

**Wind speed/direction (mph)**
**Temperature/relative humidity**
- Air temperature in degrees F
- Relative humidity in percent
- Dew point (degrees F) calculated from temperature, relative humidity

- RWIS

## Precipitation (yes/no)

Weather Identifier and VISibility (WIVIS) present weather
Type of precipitation (rain, snow, drizzle)
Precipitation intensity
Visibility in miles or increments if less than one mile

**W****eather ****I****dentifier and ****VIS****ibility (****WIVIS****) present weather**
- Type of precipitation (rain, snow, drizzle)
- Precipitation intensity
- Visibility in miles or increments if less than one mile

**RWIS SENSORS****- ****ATMOSPHERIC **continued** ****-**

- RWIS

## Weather Identifier and VIsibility Sensor (WIVIS)

**W****eather ****I****dentifier and ****VI****si****bility ****S****ensor (****WIVIS****)**

- RWIS

## RWIS SENSORS    - PAVEMENT -

**Pavement**** surface temperature in degrees F**
**Surface condition (state of road)**
- Dry, wet, dew, frost
- Snow/ice watch/warning
- Chemical factor
- Depth of moisture
- Percentage of ice in solution
- Solution freeze point
- Percent chemical in solution

- RWIS

## Subsurface temperature probe

Soil temperature (in degrees F) 18 inches below pavement surface
Some sites also have subprobe at 36 inches

- Soil temperature (in degrees F) 18 inches below pavement surface
- Some sites also have subprobe at 36 inches

**RWIS SENSORS    ****- ****P****AVEMENT**** -**

- RWIS

## Site Selection

- Power and telecommunication requirements

- Correctly choosing the best location

- common site specific problems to which common RWIS sensors are susceptible

- height of the sensor above the ground and orientation

- outside the wheel path of vehicles, at a location that is known to freeze early

- RWIS

## Full Sensor Suite
Weather (Visibility, Wind, Temp, Pressure, Humidity)
Imagery (Color, B&W, IR Thermal)
Traffic (Vehicle Counts, Speed, and Classifications)
Pavement (Dry, Wet, Icy, Temp)

Autonomous Operation
Intelligent Roadside Processing 
Low Power (Solar or AC)
Flexible Communications (RF, Fiber, Phone, Satellite)
Rugged Construction

**Weather **(Visibility, Wind, Temp, Pressure, Humidity)
**Imagery **(Color, B&W, IR Thermal)
**Traffic **(Vehicle Counts, Speed, and Classifications)
**Pavement **(Dry, Wet, Icy, Temp)
- Autonomous Operation
**Intelligent Roadside Processing **
**Low Power **(Solar or AC)
**Flexible Communications **(RF, Fiber, Phone, Satellite)
**Rugged Construction**

**Advanced Roadway Monitor**

**Fixed Installation for Virginia DOT**

**Complements of WeatherScene®**

- www.mcq-sii.com

- Applications & Resources

## Typical InstallationI-40 / Riordan AZ

- Sensors

- Folding Tower

- Electronics Cabinet

- Electronics Cabinet Interior

**Complements of WeatherScene®**

- Applications & Resources

## Sensor Installation

- Precipitation

- Color Cameras

- Weather POD

- Traffic

- Applications & Resources

## SurfaceWatchTM Non-Contact Pavement Monitor

**SurfaceWatch****TM**** ****Non-Contact Pavement Monitor**

**Infrared sensors that can remotely detect pavement conditions.**
**Suite of instruments to detect:**
- Presence of a water film on pavement
- Pavement temperature
*Concentration of deicing/anti-icing materials in water film*

- Applications & Resources

## SurfaceWatchTMInstallation

**SurfaceWatch****TM****Installation**

**Sensor Height**

**INFRARED BEAM**

**Measurement Area **
**On Road Surface**

**Pole Mounted**
**Beside or Over**
**Roadbed**

** ****Covers Full Traffic Lane**
**  ****Range of 30 – 45 Ft**
**  ****Provides Condition Data**
**           ****(Dry, Wet, Ice, Snow,   **
**                           ****Surface &   **
**            ****Sub-Surface Temp)**
**  ****No Sensors Installed in **
**                            ****Roadbed****	**

**Subsurface**
**Sensor**
**Mounted**
**1 Ft Below**
**Grade**

- Applications & Resources

## SurfaceWatchTM Applications

**SurfaceWatch****TM**** Applications**

**Bridge Decks**
**Mobile Work Zones**
**Steep Grades**
**Remote Locations**

**Trigger Warning Signs**
**Trigger De-Icing**
**Monitor Storm Progress**
**Improve Maintenance Deployment**

- Applications & Resources

## Wisconsin - 61 RWIS stations
Iowa - 85 RWIS stations
Illinois - 87 RWIS stations
Minnesota - 154 RWIS stations, 
Indiana - 24 RWIS stations
Ohio - 158 RWIS stations

**Environmental Sensor Stations (ESS) are used to observe or measure three types of road weather information: **
- atmospheric data,
- pavement data, and
- water level data.** **

**Wisconsin - 61 RWIS stations**
**Iowa - 85 RWIS stations**
**Illinois - 87 RWIS stations**
**Minnesota - 154 RWIS stations, **
**Indiana - 24 RWIS stations**
**Ohio - 158 RWIS stations**

**RWIS in the Midwest**

- Applications & Resources

##   Putting the Technology to the Test

**  ****Putting the Technology to the Test**

**  ****The Challenge**

**  ****The Benefits**

**RWIS ****network ****within Illinois**

- Applications & Resources

## Chicago area RWIS sites

- Applications & Resources

## Ohio DOT Roadway Weather Information System (RWIS) Expansion

|   | Cost |
| --- | --- |
| Weather stations deployed along highways (44 total) | $2,199,160 |
| Weather stations deployed at county offices (44 total) | $1,299,680 |
| Training | $15,200 |
| Warranty/Service Agreement | $185,000 |
| TOTAL | $3,699,000 |

**Ohio DOT Roadway Weather Information System (RWIS) Expansion**

| System Cost |
| --- |
| Project cost: $3.699 million |

- addition of 86 weather stations to the 72 already in operation, the 158 weather stations provide coverage of all 88 Ohio counties making it the largest deployment of RWIS in the U.S.

- Applications & Resources

## Applications & Resources

## Applications & Resources

## http://www.ops.fhwa.dot.gov/weather/Publications/RWIS_brochure.pdf

- Applications & Resources

## Learn More... The U.S. DOT’s ITS Standards Program has information and resources pertaining to NTCIP ESS 

- available at www.its-standards.net.
- NTCIP Document 1204: Object Definitions for Environmental Sensor Stations (AASHTO, ITE, NEMA) defines the ESS protocol. This document is available at www.its-standards.net/Documents/NEMA-TS3.7.pdf.
- An Aurora Program report on display standards, IdeDevices and Data Formats, is available at www.aurora-program.org

- Applications & Resources

## Applications & Resources

## Examples of state RWIS specifications that cite the NTCIP standards are available on the Aurora Program web site at http://www.aurora-program.org/matrix.cfm 

- Aurora is an international partnership of public agencies working on RWIS.

- http://www.ops.fhwa.dot.gov/weather

- http://www.benefitcost.its.dot.gov/ITS/benecost.nsf/SearchAll?SearchView&Query=RWIS

- Applications & Resources

## sample RWIS RFP

- sample RWIS RFP

- Applications & Resources

## Applications & Resources

## Applications & Resources

## A successful RWIS program will depend on the careful coordination of these 

**FORECASTS**

**SENSORS**

**OBSERVATIONS**

**EXPERIENCE**

**SALT USAGE**

**CONSTITUENTS**

**MATERIALS**

-  determine exactly what you need and to what accuracy

-  conduct a site survey to
- determine the optimum site for RWIS installation

-  develop a plan for long-term support of the RWIS

- A successful RWIS program will depend on the careful coordination of these
- three essential areas.

- Applications & Resources

## Benefits of RWIS

- 4-11

**Mobility**

**Economic Vitality**

**Safety**

- Applications & Resources

## http://knowledge.fhwa.dot.gov/rwmo

- This community is dedicated to the open exchange of information and knowledge on road-weather management, operations and research related information.
- Please register at the associated Directory.  The Directory provides e-mail addresses and organizational affiliations of participants and facilitators.

**http://knowledge.fhwa.dot.gov/rwmo**

- The goal the Road Weather Management and Operations (RWMO) Community of Practice (CoP) website is to encourage discussions related to weather-surface transportation issues and opportunities, to foster and contribute significantly to the research, development and implementation of related technologies and innovative practices. All are welcome to post comments and updates.

- Ray Murphy ray.murphy@fhwa.dot.gov