Group Transit - Average Speed Calculator
This spread sheet will enable you to quickly determine the true average speed and time it takes to get somewhere when traveling on any group transit system such as light rail. It is absolutely meaningless to promote something like light rail and only talk about its top cruising speed. One must take into account:
1. The time spent accelerating from the station after you boarded;
2. The time spent at cruise speed before the vehicle has to start slowing down to drop people off and let people on at the next station;
3. The time spent slowing down to a stop; and
4. The time spent in dwell at the station while passengers are exiting and new passengers are boarding.
5. The amount of time spent waiting for the group transit vehicle to arrive.The following example was prepared for the proposed Seattle Monorail with the help of resident John Kropf.
It is assumed that the person wants to travel from one of the line to the other end - the full 8.5 miles.
Note that the acceleration and deceleration level used in these calculations is 1/8th g. This is the allowable standard for transit vehicles where passengers may well be standing or walking in the aisles.
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Group Transit - Average Speed Calculator |
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by Douglas J. Malewicki, AeroVisions, Inc., July 2, 2002 |
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INPUTS |
Calculated Conversions |
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Length of route (L): |
8.5 |
miles |
L: |
44,880 |
feet |
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Number of stations (N): |
12 |
# of accel & decel segments: |
11 |
(N-1) |
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Dwell time at each station (DT): |
60 |
seconds |
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Max cruise speed (Vmph): |
50 |
MPH |
V: |
73.333 |
ft/sec |
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accel and decel g level: |
0.125 |
g's (1g= 32.2 ft/sec2) |
a: |
4.025 |
ft/sec2 |
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Time to accel to max cruise speed (t): |
18.219 |
seconds |
[formula is t = speed/accel] |
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Distance used to accel to cruise speed (s): |
668.05 |
feet |
[formula is s = 1/2 accel (t^2)] |
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Total time in accel and decel (sum of t): |
400.83 |
seconds |
[formula is t*2*number of segments] | |||||||
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Total distance in accel & decel (sum of s): |
14,697 |
feet |
[formula is s*2*number of segments] | |||||||
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Remaining distance at max cruise: |
30,183 |
feet |
[formula is L - sum of s] | |||||||
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Time spent at max cruise speed: |
411.59 |
seconds |
[formula is (L - sum of s) / V] | |||||||
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Extra time unloading/loading at stations: |
720.00 |
seconds | [formula is # of stations * dwell time at each] | |||||||
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Total time for trip (Ttotal): |
1,532.41 |
seconds |
[Sum of times spent in accel, cruise, decel & dwell] |
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Ttotal: |
25.54 |
minutes |
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Ttotal: |
0.426 |
hours |
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True average speed (VAVEmph): |
19.97 |
MPH |
[formula is length of route/total trip time] |
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Rush hour average waiting time: |
120 |
seconds |
[half of the 4 minutes between trains] |
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Realistic trip time: |
1,652.41 |
seconds |
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27.54 |
minutes |
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0.459 |
hours |
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New average speed: |
18.52 |
MPH |
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Other time of day average waiting time: |
240 |
seconds |
[half of the 8 minutes between trains] |
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Realistic trip time: |
1,772.41 |
seconds |
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29.54 |
minutes |
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0.492 |
hours |
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New average speed: |
17.26 |
MPH |
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Worst waiting time: |
480 |
seconds |
[just missed it & must wait 8 minutes till next train] |
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Realistic trip time: |
2,012.41 |
seconds |
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33.54 |
minutes |
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0.559 |
hours |
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New average speed: |
15.21 |
MPH |
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CLICK HERE
to download this Excel Spreadsheet
so you can do your own
predictions
for Public Group Transit average speeds
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In case
you want to compare how a much lower cost SkyTran system |
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| Number of stations (N): | 0 |
SkyTran is non-stop. You never stop at intermediate stations. |
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| Dwell time at each station (DT): | 0 | seconds | No stopping AND therefore no waiting for people to get on and off at each and every intermediate station. It just speeds by them all! |
| Max cruise speed (Vmph): | 100 | mph | (and don't forget SkyTran gets 200 mpg equivalent energy efficiency while traveling at 100 mph!) |
| accel and decel g level: | 0.5 | g's | This is less than the acceleration and deceleration felt in a Corvette or any other good sports car. The 0 to 60 mph time with 0.5 g acceleration capability is 5.5 seconds which is nothing exceptional for a modern sports car. |
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The last three boxes of the spreadsheet are meaningless for SkyTran, since you never have to wait for a scheduled group transit machine to arrive and you can never MISS a SkyTran. Think of a line of Taxis waiting in line for you! |
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(Coming soon - the SkyTran PASSENGER CAPACITY PER HOUR calculator)