Supplementary Safety Measures (SSMs)

A list of
 approved SSMs to be installed on all approaches to an at-grade crossing, with associated effectiveness,
is as follows
:
  • Temporary closure of at-grade crossing during hours which Partial Quiet Zone is in effect (Effectiveness: 1.0).
  • Four-quadrant gate systems with no presence detection (Effectiveness: 0.82).
  • Four-quadrant gate systems with presence detection (Effectiveness: 0.77).
  • Four-quadrant gate systems with traffic of at least 60 feet with or without presence detection (Effectiveness: 0.92).
  • Gates with channelization devices (Effectiveness: 0.75).
  • Gates with non-traversable curbs with or without channelization devices (Effectiveness: 0.80).
  • One way street with gates (Effectiveness: 0.82).
  • Permanent closure of at-grade crossing (Effectiveness: 1.0).
The effectiveness represents the ability of the SSM to reduce
at-grade
 crossing crashes. For example, closing a crossing reduces 100% of at-grade crossing crashes while installing gates with channelization devices reduces 75% of crashes. Effectiveness values are subject to change by the FRA.
The following requirements apply when installing SSMs:
  • All approach and exit lanes must be covered by gates in a four-quadrant system.
  • Horizontal distance between two gate ends must not be more than 2 feet.
  • Horizontal distance between a gate and a raised median or channelization device or curb must not be more than 1 foot.
  • Medians or channelization devices must extend at least 100 feet from gate arm, or if there is an intersection within 100 feet of gate, the median or channelization device must extend at least 60 feet from gate arm.
  • Non-traversable curbs must be 6-inches height minimum and only used when the roadway speed limit is 40 mph or less.
  • Any streets, alleys, or commercial driveways within 60 feet of at-grade crossing (parallel with rail) must be closed if medians or channelization devices are proposed.
  • Non-traversable curb must extend back 100 feet from gate if only one gate is used on a one-way street.