Conventional transportation systems such as subway trains and buses are now designed to accelerate at about 4 ft/sec/sec (3 mph/sec). Electrically powered rapid transit cars of the last 10 years have an initial-acceleration range of 2.5 to 3.2 mph/sec (0.11 to 0.14 g). This performance will accelerate a vehicle to a speed of 30 mph in 10 seconds. Crucial to the longitudinal acceleration level that can be accepted by passengers is the preparedness of the passenger at the onset of motion. When the traveler is seated and expectant, the smooth takeoff of a jet airliner is not at all uncomfortable, although at 0.5 g some difficulty would be found in leaving the seat. Nevertheless, when the trains in the Paris metro system were fitted with rubbertired wheels and acceleration was increased, complaints forced a return to the previous standard of about 3.3 mph/sec that had been used with steel wheels. Sudden jerks on starting or stopping are especially objectionable, since they can cause an unwary standee to lose his balance. Longitudinal accelerations and decelerations judged comfortable and acceptable on the basis of rider ratings were in the range of 0.11 to 0.15 g, and lateral accelerations were in the range of 0.06 to 0.22 g. However, existing data are inadequate for specifying acceleration limits for future systems. Since the acceleration values found are about 0.10 g lower than those that are accepted by automobile users, it may be worthwhile to investigate methods for making higher accelerations acceptable to mass transportation passengers.

  • Corporate Authors:

    Applied Physics Laboratory

    8621 Georgia Avenue
    Silver Spring, MD  United States  20910
  • Authors:
    • Gebhard, J W
  • Publication Date: 1970-2

Subject/Index Terms

Filing Info

  • Accession Number: 00044187
  • Record Type: Publication
  • Source Agency: Urban Mass Transportation Administration
  • Files: TRIS, USDOT
  • Created Date: Jun 15 1976 12:00AM