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Thread: Estimating average daily traffic

  1. #1

    Estimating average daily traffic

    I am using hardcopy DOT traffic volume maps and attempting to get a estimate of average daily traffic for a 7 mile loop that incoporates local, state and US highways/bridges. Should I total the 11 segments (as deliniated by the DOT) and divide by 11 OR should I total the AADT and divide by 7 (as in 7 miles)? Or another way?

  2. #2
    Sep 2008
    Anchorage, Alaska
    So, you have 11 segments over 7 miles each with different AADTs for the same year that you are concerned with? How many access points are there along these 7 miles, and how different are the AADTs?

    the units for AADT have nothing to do with miles, so dividing by 7 would give you a bogus value. Dividing by the 11 segments would give you an average over the entire length if that is something you are after, but I would strongly suggest just using the greater of these 11 values.

    Remember that you are looking at Average Annual Daily Traffic. The peak yearly volume will of course be much higher.

  3. #3
    Cyburbian DetroitPlanner's avatar
    Mar 2004
    Where the weak are killed and eaten.
    Another suggestion:

    If you're looking at a loop of various roads, these will have various capacities based upon roadway conditions. For example 20,000 on a 4 lane road with lots of traffic signals will have a lot more congestion than 20,000 on a six lane freeway. A traffic count by itself does not mean much. If you can compare it to a roadway's capacity, then you have meaningful data. This is typically shown as a vehicle to capacity ratio, I would suggest maybe looking at each segment seperately, that way you can address transportation needs of each individual segment because one segment may operate just fine, and another may need some help.
    We hope for better things; it will arise from the ashes - Fr Gabriel Richard 1805

  4. #4

    Thanks for the input

    Thanks everyone for the input.

    What we decided to do was use a weighted average of the segments to get a generalized estimate. It's just for discussion purposes, a more exact number would be created through this study. The AADT are all between 15,000-25,000.
    7 miles of major road travel through 6 municpalties and have 42 local roads intersecting...ugg! a mess is what it is!

    First time in a few years I've dealt with infrastructure projects. Guess I couldn't expected to hug trees forever! .

  5. #5
    Cyburbian The One's avatar
    Mar 2004
    Where Valley Fever Lives


    Where's Rumpy when we need him???

    Skilled Adoxographer
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