Driveways on Urban streets

Safety performance functions, development (calibration, crash modification factors [Part C], crash proportions), IHSDM and other software

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Driveways on Urban streets

Postby dengstro » Wed Feb 15, 2012 4:54 pm

What is the method for counting driveways along a divided arterial? Are full access versus partial access driveways counted differently?
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Re: Driveways on Urban streets

Postby mdimaiuta » Wed Feb 22, 2012 2:25 pm

My understanding is that full access and partial access driveways along a divided arterial are counted the same. I do not see any distinction made in HSM Chapter 12. As you are probably aware, HSM p. 12-23 notes only that "the number of driveways of a specific type is the sum of the number of driveways of that type for both sides of the road combined. The number of driveways is determined separately for each side of the road and then added together."

Mike Dimaiuta
FHWA Geometric Design Lab - IHSDM/HSM Support
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Joined: Tue Nov 30, 2010 1:50 pm

Re: Driveways on Urban streets

Postby dengstro » Thu Feb 23, 2012 4:36 pm

Thanks MIke, you have confirmed what i was thinking. It's something that should be reexamined in future updates.
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Re: Driveways on Urban streets - Oregon SPFs

Postby benpdx » Tue Aug 05, 2014 1:34 pm


Great question, thanks for sharing.

Here in Oregon, ODOT has created more detailed SPFs for driveways on highways. This is part of a move to include better safety evaluation as a part of access management. I don't recommend using this directly, but it does provide some information on how you might approach a similar topic in your location.

The report is online here:

There is also a spreadsheet available that automates these SPFs, but I am not sure exactly where to find it. Sorry.

Hope this is helpful,

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