How to incorporate stop signs in a service area analysis

[CathleenAlmberg]

I'm creating service areas for an emergency response entity, based upon areas that can be reached in 5 minutes. That is easy enough, however I am not sure how to incorporate stop signs into the analysis. Do they go in as Point Barriers / restrictions? And how should they be attributed?

thanks for the help

[RamB]

you can cut a little piece of line segment just beneath the stop sign and assign it abnormally high value of resistance (say 1000 minutes) ... you can do this both direction or one direction as your situation demands. 🙂

regards

[JoeBorgione]

I'm creating service areas for an emergency response entity, based upon areas that can be reached in 5 minutes. That is easy enough, however I am not sure how to incorporate stop signs into the analysis. Do they go in as Point Barriers / restrictions? And how should they be attributed?

thanks for the help

That's what I would do; if you have a point feature class for your stop signs, you are almost there.  See:

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//004700000056000000

[RamB]

I would not advice using point barriers for two reasons:

1. Stop signs are directional restrictions and the best way to do this is building them into network segments and giving directional control (AB may have stop sign but BA may not)
2. Stop signs do not mean a road stops there, instead a vehicle has to stop and proceed (wait time)

regards

[CathleenAlmberg]

Thanks for the good information, I ended up loading stop signs as cost point barriers. Which leads to the next issue, what is a good amount of time to attribute to stopping at a stop sign? Most of the roads are residential. For instance, I guess-timated that it takes 5 seconds to stop, 5 seconds at the sign, and 10 seconds to accelerate to the speed limit. Now this is guessed and very general, are there any good sources / formulas out there?

And here's another thought. The roads have FClass classification, which are Florida Road classifications. The classes are

'LOCAL', 'LOCAL UNPAVED', 'MAJOR ARTERIAL', 'MAJOR COLLECTOR', 'MINOR ARTERIAL', 'MINOR COLLECTOR', 'PRINCIPAL ARTERIAL'

Does anyone know of previous analyses that have been done, that calculated average Minutes based upon road classification? That would be ideal.

thanks for the help!

[RamB]

Uhmm, probably not an issue. I suggest you to take out a day, select a few intersections within your study area. Take measurements observing vehicles with a stop watch. for half hour at each location. This way, you will have more confidence on your assumptions (no longer assumptions if you do  this survey) . Forms for such survey are readily available in National Codes established by National bodies that engage in transportation survey methods and formulations of the country or state as applicable.

regards,