A transit signal priority system in Helsinki, Finland reduced delay by 44 to 48 percent, decreased travel time by 1 to 11 percent, and reduced travel time by 35,800 to 67,500 passenger-hours per year.

FINDINGS

Delays, Travel Time, and Reliability

Delays at signals were reduced by 44 percent (1 min 13 sec) on the tramline, and 48 percent (3 min 18 sec) on the bus line. However, stop time for both modes increased slightly (3 to 5 sec) since drivers ahead of schedule increased their stop time to balance routing schedules.

Total travel times decreased 1 percent (21 sec) on the tramline, and 11 percent (3 min 18 sec) on the bus line. The reduction was primarily the result of reduced signal delays.

On-time arrival improved by 22 percent on the tramline, and 58 percent on the bus line.

Based on reductions in signal delay, travel time savings were estimated at 9 seconds per kilometer (sec/km). Since approximately 27 million passenger-miles per year accrued on the 8.1 km section of tramline; the system saved an estimated 67,500 passenger-hours per year. Correspondingly, the bus line saved 35, 800 passenger-hours per year.