Quantifying Access Management Benefits Using Traffic Simulation

The San Antonio - Bexar County Metropolitan Planning Organization has identified several developing corridors to be designed using access management techniques. This action is a result of several existing arterial corridors which already have congestion problems associated with uncontrolled access to adjacent land uses. The Bitters Road corridor in northern San Antonio is a five-lane arterial that has 37 access points and five at-grade signalized intersections within a one-half mile section. Several businesses along Bitters Road resort to hiring off-duty law enforcement officers to direct traffic to ensure vehicles can safely enter their business. A traffic analysis was conducted to quantify the extent of delay experienced along Bitters Road and the expected improvements to traffic operations if access management techniques were implemented. These expected improvements to the existing corridor would be used to justify the use of access management techniques to the developing corridors within the San Antonio area. The traffic analysis began with analyzing the existing conditions. Two traffic simulation programs, Netsim and Synchro, were utilized to develop AM and PM peak hour models of the corridor. Two conceptual scenarios were also developed and analyzed using both software programs. The first scenario was a retro-fit of the existing condition, with many driveways consolidated or eliminated. The second scenario removed all driveways and utilized parallel backage roads to provide access to the adjacent land uses. Several measures of effectiveness including travel speed, delay, emissions and volume were used to estimate the benefits of the two scenarios. The benefits of the scenarios were then used to predict the likely traffic operations along the developing corridors if access management techniques were utilized.