Draft Canadian Railway-Roadway Grade Crossings Standards ...

(c)
(d)
Where,
SSD is obtained from section 4.4.
Grade Crossing Design Vehicle Length is obtained from Table 4-1.
The gate arm clearance time from the SSD:
Gate Arm Clearance Time from SSD = Gate Arm Clearance Distance/Maximum
Road Operating Speed (s)
The gate arm clearance distance from a stop is calculated as follows:
Gate Arm Clearance Distance from a stop = 2 m + Grade Crossing Design Vehicle
Length (m)
Where,
Grade Crossing Design Vehicle Length is obtained from Table 4-1
Gate Arm Clearance Time from a stop equals the time for the grade crossing design
vehicle to accelerate and travel completely through the gate clearance distance.
While Stopping Sight Distance includes perception reaction time for a driver stopped
at a crossing, the decision to proceed would be made only after determining that the
warning lights are not flashing. At this point in time, the driver should be set and
begin to move without delay. There should be sufficient time for the vehicle to
clear the gate arm before it would strike the vehicle.
Calculation of the Gate Arm Clearance Time for stopped vehicles should be done at
the same time as the calculation of the Design Vehicle Departure Time for the grade
crossing under section 4.7.
The time required for stopping or accelerating vehicles on descending or ascending
grades must be considered. Refer to sections 4.4 and 4.7 and also to the Geometric
Design Guide for calculating the effect of gradient on stopping sight distance or
acceleration, and to calculate the gate delay requirement for other special vehicles.
The delay of gate arm descent from the time of activation of the flashing lights is provided
in Table 4-8 for level road approaches.
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