Motorcycle Vehicle Miles of Travel in Traffic Safety Reports

Motorcycle Vehicle Miles of Travel, VMT, are often used as a comparison to show the increase or decrease of accidents that cause injuries and fatalities

from year to year in many traffic safety reports.  The accuracy of motorcycle VMT has always been questionable in these reports.

The Highway Performance Monitoring System, HPMS, sets the requirements the states need to report to the Federal Highway Administration, FHWA.

In the HPMS field manual under “Travel Activity By Vehicle Type” motorcycle miles of travel is optional. [1] This is why some states have “0 VMT” listed

in that category. Due to the authorization of SAFETEA-LU, The Federal Highway Administration is conducting a reassessment of HPMS which is to be

completed in late 2007. One of the concerns addressed at the reassessment meetings with the states was the lack of motorcycle data and the quality of the

data that was collected by the states. Their answers are as follows:

Hartford meeting: Do you have motorcycle data?  [2]

CT – Has some count stations, reports it area wide.

MA – Not reporting. Some data is being collected; however, there are quality issues with it. Most motorcycle traffic is on weekends and it is not really

    collected on the weekends.

NY – Uses Piezo and can classify motorcycles. They are starting to test equipment and look into routine collection of motorcycle data as part of classification files.

PA – Collects Scheme F, no motorcycles.

VT – One of the classes collected is motorcycles, however, due to equipment constraints, they cannot get both good motorcycle and truck data.

    The Jamar counters can only be set to collect one or the other.

Atlanta meeting: Do you collect motorcycle data? What are the issues with this? [3]

AL – No

FL – Yes

GA – Yes

SC – Yes

TN – ?

VA – Yes

What do you feel is the quality of your motorcycle data?

The group agreed that the quality of motorcycle data is dependant on operating classification sites and there are many issues associated with keeping

the sites operating properly.

Lincoln meeting: Do you have motorcycle data? Quality? [4]

KS – Yes, using automated machines. It is not one of the classes tested for accuracy. They are looking at overall and type 9. Motorcycles are a small

    percentage anyway. They tend to be a “catch all” if they don’t meet other classes. They don’t worry about it since it is not important, however,

     it is probably better than not reporting anything.

MI – Yes, on SHS. Equipment is not reliable so quality is questionable.

MN - Yes

NE – Yes, from 2 sources. Reported based on manual counts (short term weekday only, adjusted using continuous classifiers). Quality is somewhat

    suspect as factor includes other vehicles.

NY – Yes and reports it. They do an order of magnitude checks. Limited to weekday counts.

WI – Yes, but same issues with classification. Quality is not reliable.

WY – Yes, NE part of state (Sturgis) have optimized counters and loops to get better information. Should be reported in Areawide table but not

    sure if it is. Quality is probably pretty high. Sturgis definitely shows up in permanent counts.

Portland meeting: Do you have motorcycle data? What are the issues with this? [5]

AK – Yes, those at WIM sites are accurate, others not

CO – Yes, however, automated data collected in urban areas not doing a great job. All vehicle classes could be better.

ID - Yes

MT – Yes, no issues

NV – Yes

OR – Yes, this is the class that is most variable – site specific data is likely not great, average may be OK

TX – Not reported, automated classification is not good. Manual counts are done when motorcycles counts are higher.

WA – Yes, but they are expanded and not great quality.

The HPMS Draft Recommendations Report has recommended making it mandatory for states to provide motorcycle VMT data in 2008 instead

    of waiting until the required mandatory year of 2010. [6] The states have until June 30, 2007 to comment on the draft proposal.  If motorcycle

    vehicle miles of travel do become mandatory, the quality of the motorcycle data collected should be reviewed.

In summary, any traffic safety report or article that uses motorcycle VMT to establish an increase of motorcycle accidents is false due to some states

not submitting data and some data not being accurate.

1. Highway Performance Monitoring System Field Manual: www.fhwa.dot.gov/ohim/hpmsmanl/hpms.htm

2. Hartford Summary: http://dmses.dot.gov/docimages/pdf96/401528_web.pdf

3. Atlanta Summary: http://dmses.dot.gov/docimages/pdf96/401592_web.pdf

4 Lincoln Summary: http://dmses.dot.gov/docimages/pdf96/401649_web.pdf

5 .Portland Summary: http://dmses.dot.gov/docimages/pdf96/401650_web.pdf

6  HPMS Draft Recommendations Report:  http://dmses.dot.gov/docimages/p88/436214.pdf

Karen Leonard

New York Freedom Riders