Based upon Dallas Area Rapid Transit (DART) and Texas Transportation Institute data, it is estimated that the existing light rail lines are removing approximately 0.1 percent of traffic volume in the Dallas area (not Dallas-Fort Worth). This represents 2.3 percent of the 1995-7 average daily increase in vehicle miles (latest data available).
This means that DART’s light rail lines have removed the equivalent of 8.3 days of traffic growth in the Dallas area. It is thus estimated that the traffic volume level that would have been reached on June 22, 1998 without light rail was postponed as a result of light rail to June 30, 1998 The capital cost per day’s volume of traffic is an estimated $102 million.
Traffic Volume and Air Pollution Levels Reached on this Day without Light Rail June 22, 1998 Are Estimated to Have Been Reached Instead on this Day as a result of Light Rail June 30, 1998 Days of Traffic Growth that Nullify Light Rail’s Traffic Reduction Impact: 8 Cost per Day $102,000,000
Calculations and methodology are shown below
Annual Light Rail Passenger Miles
58,916,771
1998 National Transit Database Estimated Weekday Passenger Miles
196,389
Annual divided by 300 Auto Driver Diversion Rate
35.5%
DART Survey: Assumes 0.5 Driver Car Pool Ratio Light Rail Transfer from Drivers: Vehicle Miles
69,708
Weekday Passenger Miles times Auto Driver Diversion Rate Annual Daily Increase in Roadway Vehicle Miles
3,000,000
Texas Transportation Institute: 1995-7 Annual Rate Light Rail Related Reduction in Roadway Vehicle Miles Relative to Growth in Vehicle Miles
2.3%
Light Rail Transfer Divided by Total Travel Days of Traffic Volume Increase Transfered to Light Rail
8.3
Percentage Reduction times 365 Capital Cost per Day of Traffic Volume Reduction
$102,000,000
Days of Traffic Volume Reduction Divided by Light Rail Capital Cost