|Max acceleration m/s2|
|Max service deceleration m/s2|
Safest, stopping distances consistent with other vehicles, mostly 40km/hr max speeds|
Fairly safe, 40 and 50km/hr max speeds
Thrill-seeker (emergency braking distance of 100m - Capital Metro's proposal) - 60 and 70 km/hr max
|Max speed km/h||Signal time (sec)||Time Arrive||Delay (sec)||Time Leave||Travel to next node||Note|
|On entry (km/h)||On route (km/h)||Green||Red||Station||Signal||Time (sec)||Average speed (km/h)||Top speed (km/hr)||Start speed (km/h)||End speed (km/h)||Accel time (sec)||Cruise time (sec)||Decel time (sec)|
The LRV column is used for "green time" (with 6 secs added as noted above for travel uninterrupted by stations, as noted above). "Red time" is the sum of all green light times for traffic crossing the light rail (but if 2 flows have simulatenous greens, only one is counted) plus 3 seconds to represent the amber time for each different flow. For example, at Antill road crossing, the LRV green time is 41 sec. W-E and W-S traffic (Mouat to Northborne South) has 25 sec green. E-W and E-N traffic (Antill to Northborne North) has 13 sec green. N-W and S-W both cross rail line and have simultaneous 13 sec green. There are 3 amber times to be waited. So, red time per cycle seen by tram takes 25 + 13 + 13 + 3 x 3 = 60 sec.
There are no instructions with the tables on how to interpret the LRV time, so I am assuming that for the EIS model purposes, it really does indicate the average green time per cycle seen by the tram.
In determining whether tram will stop at a signal, or instead travel through the intersection at 40km/hr, the green time is added to the red time to produce a total signal cycle time. A random number is generated and scaled to the total cycle time. If it falls in the "green" section of the cycle, the tram does not stop. Otherwise, a random wait, on average half the red cycle time, is incurred.
Light rail vehicles such as the Flexity and Urbos manufactured by the short-listed consortia typically have emergency brake deceleration rates of between 2.4m/s2 and 2.7m/s2. Their loaded weight far exceeds that of any semi-trailer or bus, and is about the same as a laden B-double truck and trailer: 50 - 60 tons. The Australian Design Rule 35 requires heavy vehicles, such as semis and B-doubles, to have an effective peak deceleration rate of at least 4.4m/s2. If such a vehicle, or indeed any vehicle to be operated in an urban setting, was tested at only 2.4 - 2.7m/s2, it would be considered defective.
From the Capital Metro website descriptions and images, I have not seen any suggestions of physical barriers along the route between the light rail and other vehicles, pedestrians and cyclists, quite the opposite.
It seems very unlikely that the community or the police would countenance a stream of heavily-laden B-doubles travelling along Flemington Rd at the posted speed limit of 70km/h with highly defective brakes, at 3 minute intervals in peak periods.
Although the light-rail runs in its own lanes, there are about 30 intersections and crossings along the route and opportunities for accidents that could be avoided if the light-rail vehicle travelled at a speed commensurate with its braking distance, and hence didn't have an extremely long stopping time from 70km/hr of at least 8.7 seconds and a stopping distance of at least 99m (assuming the standard 50% percentile reaction time of 1.5sec, level track, good conditions and the higher emergency braking capability of 2.7m/s2). Unlike a car, bus or truck, the driver of the light-rail has no option to swerve to avoid a fallen cyclist, a stalled car, a pram stuck on the track or a pedestrian wearing ear-phones and distracted by texting. The momentum of a laden light-rail vehicle is over 35 times that of a typical car travelling at the same speed.
To be explicit, whilst travelling at 70km/hr, the tram driver may notice a cyclist fall 85m in front of their 55 ton vehicle, and apply the emergency brakes. Assuming the standard 1.5 second reaction time to observe, decide to apply and then activate the emergency brake, and assuming a level track and good conditions, the light rail vehicle will still be travelling at 31km/hr when 5.5 seconds later it collides with the fallen cyclist, carrying more kinetic energy into the collision than a 2 ton SUV travelling at 160km/hr.