Unintended consequences: learning from managing traffic volumes on express toll lanes

By Mary Ebeling

Despite the prevalence of anti-tolling sentiment reported in the press, cities like Atlanta and Los Angeles that operate variably priced toll lanes have seen early skepticism give way to heavy use of these lanes by commuters. These successes and the approaches taken by the two agencies to manage increasing demand suggest a need to manage these facilities in the context of the entire transportation system. The two approaches taken by Atlanta and Los Angeles could be used by other agencies struggling with similar issues.

The I-85 toll lane in Atlanta opened in 2011 and initially struggled to attract users.  At one point the tolls were as low as a penny per mile during off peak hours. Now the State Road and Tollway Authority (SRTA) reports more than 23,000 daily trips and is struggling to keep express lane speeds at or above the target speed of 45 miles per hour. Two years ago the Los Angeles Metropolitan Transportation Authority (MTA) converted the carpool lane on the 110 Freeway into toll lanes, allowing SOV drivers to use these lanes. MTA initially experienced a similar lukewarm response. However MTA now cites challenges similar to what SRTA is experiencing.

Both transportation authorities are currently adjusting their policies to manage the growing congestion in the lanes. SRTA has launched a pilot program that promotes greater use of public transit as a way to free up space in the toll lane. The program offers up to $10 a month in toll credits if drivers choose to take one of the available express buses instead of driving. SRTA wants people to try transit and hopes this program will be an inroad into a mode shift for some commuters.  SRTA also has found partners in the Midtown business district and employers to help promote the program.

The MTA has taken a different approach to managing the 110 Freeway toll lanes. In addition to reviewing the algorithm used to dynamically set tolls, the agency is considering converting this lane to a carpool-only lane during rush hour as an alternative to increasing tolls to manage demand. Part of why the MTA is considering a conversion to carpool lanes versus simply increasing the tolls stems from the very real concern that a significant group of users—contractors, consultants, and those billing others—are not sensitive to the price signals of rising tolls. These drivers bill clients for their travel, rather than paying out of their own pockets. This phenomenon can skew pricing upward and reinvigorate the “Lexus lanes” debate from the early days of this tolling strategy.

Toll lanes are popping up around the country. In addition, states like Washington are considering converting some HOV lanes into managed toll lanes, allowing SOVs to utilize the lanes. These states and regions may find lessons from Atlanta and LA helpful with managing travel demand in these lanes.

Mary Ebeling is a Transportation Policy Analyst at SSTI.