Office of Operations
21st Century Operations Using 21st Century Technologies

Commuter Link - Salt Lake City, UT

FAST FACTS ABOUT: Commuter Link - Salt Lake City, UT
Types of TDM:
Advanced Traveler Information Systems
Keywords: Real-time communication, multi-jurisdictional coordination, technology, individualized demand management.
Area Demographics:
Salt Lake Area: 913,000 residents
Program: Technology allows SOV drivers to make better choices by managing their own demand with real time travel information.
Cost of Program: In 2004 the reduced cost of server technology makes this a much less expensive endeavor. Instead of requiring nearly a dozen Unix Servers to capture/generate images and nearly 40 Intel web severs to operate CommuterLink, TOC employees intend to operate all it with 3 or 4 more powerful Intel servers at an approximate cost of $60,000. Implementer (s): Utah Department of Transportation (UDOT) in partnership with Utah Transit Authority (UTA), Salt Lake City, Salt Lake County, Wasatch Front Regional Council, Mountainland, Utah Department of Public Safety (DPS), Federal Highway Administration (FHWA), Federal Transit Administration (FTA), Federal Railroad Administration (FRA), Salt Lake City Airport, ITS Rocky Mountain, ITA America, and Georgia Navigator.
Contact: Troy Hyer –UDOT, Paul Jencks–UDOT, Brian Chamberlain–UDOT.

Background Information
The CommuterLink system design was based on Navigator, the Georgia Department of Transportation’s Intelligent Transportation System, which was used for the 1996 Summer Olympics in Atlanta. With a deadline to have the system operational by the 2002 Salt Lake City Winter Olympics, UDOT staff felt it was better to go with an older model that had been tested than to trouble shoot newer technology and deliver less than adequate service to travelers during the Olympics. UDOT employees customized Georgia’s software to address their needs and added the feature that automatically disseminates alerts via email.

Advanced Traveler Information System Issues
Timing- Traffic reports on commercial radio stations are provided at specified intervals of time. Most often, traffic reports are not broadcast more frequently than every 10 minutes during peak rush hour. If an incident is reported one minute after the last traffic report is given on that station, it will be 9 minutes before commuters hear about it in the next report. That interval of time is often when commuters initiate their trip and make their decisions on which routes to take. Thousands of commuters may have made different travel choices had they heard the information. Instead they are choosing a route that will take them to and contribute to worsening delays at the incident. Receiving the traffic report as soon as the incident is reported gives commuters more opportunity to avoid it and lessen impacts of it.

Simplicity- Radio stations often have to cater to their regional audience, and therefore provide traffic reports on all of the roads in the region. This is often rushed and confusing to listen to. If for some reason you were distracted when they said something about your route, it will be ten minutes before you can hear it again.

UDOT recognized that in order to effectively manage traffic it is as important to allow travelers to manage their own demand. This can be done by providing travelers with information when and where they need it. UDOT in partnership with numerous other organizations developed CommuterLink as a centralized system to manage travel in the region.

Description of CommuterLink Website
In addition to traffic monitoring and incident detection, CommuterLink also provides a user friendly format to relay the information detected and monitored to the traveling public. This is done through the CommuterLink Website. The CommuterLink Website (CLW) is operated by UDOT, on computer servers located at the TOC. CLW provides a map of the freeway system and the major surface streets, where most of the surveillance equipment is installed. CLW offers three primary types of information to the traveler:

1. Traffic conditions (speeds, incidents)
2. Roadway closures and construction
3. Weather (including pavement conditions)

Traffic information is presented in a number of ways. To display congestion conditions, the speed on each freeway segment (about one-half mile long) is shown as color-coded band (red = 0-30 mph, yellow = 31-50 mph, and green = 51 mph and above). Incidents are denoted with a red triangle; if the user clicks on that symbol, further information about that incident is displayed on a small portion of the screen, in the lower left corner. Visitors to CLW can also view video footage of real-time traffic conditions by clicking on the cameras located on the map.

Roadway construction and closures are displayed as a color-coded triangle, near the location involved. Yellow triangles denote current construction and/or closures; blue triangles identify future construction or closures.

Weather conditions are displayed as a cloud near the roadway where road conditions are provided.

Alert System
The CLW also enables individual users to subscribe to an “Alert” system, which automatically sends an email message in the event of an incident that falls within user-specified parameters (time of day, day of week, severity of incident). CommuterLink provides information only about the routes with a traffic impact level that concerns the subscriber at a time when it concerns them. The criteria for which an individual can subscribe can be seen at right.


When an “Alert Subscriber” presses the “Create Profile” button they are added to the CommuterLink database. Every half hour subscribers who checked that “Notification Timeframe” box are activated. Within that half hour, CommuterLink captures information about travel speed on regional roadways every 20 seconds. If travel speed on any of those roadways indicates an incident, CommuterLink sends an email is sent to the subscriber. A sample message would be, “Crash I-15 at 1500N SPGVL on right shld.”

A variation on receiving this information is an email account allows users to receive this information on their cell phone or pager using text messaging. This provides them with the information they need, when they need it, wherever they may be.


By receiving emails at work before they leave to get in their car, commuters can make a decision to delay their departure until incident is cleared or plan an alternative route to avoid the incident. In either case the traveler is not adding to the problem created by the incident and able to use their time more productively. Similarly, by having the information sent to their pager or cell phone, commuters can receive information about an incident before they leave the office or while they are on the road. If they receive it early enough they can receive the same benefits listed above.

Quick Facts*
• CommuterLink initiated email subscriptions in late 2000.
• In March 2004, CommuterLink had 6,652 commuters subscribing for traffic incident information to be sent to their email account.
• CommuterLink had 121,117 visitor sessions during March of 2004. Averaging 3,907 sessions per day.
• 83% of the sessions occur during the week with Monday and Wednesday being the busiest days
• CommuterLink receives its most visitor sessions between 7:00 am and 6:00 pm. Peak usage is be- tween at 4:00 pm and 5:00 pm for commuters to plan their trip home.

*Detailed usage statistics for the CommuterLink Website are maintained by the website host (UDOT), using the “Webtrends” tracking software package. All usage data reported in this section are based upon the information reported by that system.

Office of Operations