Category: Uncategorized

I have some questions/concerns/misgivings about helmet usage as it relates to bicyclist safety and crash reports. It seems to me that it is not well-reported… (update; sometime in the late 2010s this was updated; skip below to the 11th edition…

Arizona Crash Report (10th Edition)

Curiously, given the hoopla intense interest surrounding bicyclist helmet usage, there is NO place on the ACR to report whether or not a bicyclist was using a helmet. There is a block for each traffic unit(4dd) and passenger(5c), SafetyDevice  lists things like helmet/airbag/seatbelt and so forth. However, this block is always supposed to be coded 0/Not Applicable, and is explicitly never to be 1/None Used, or 5/Helmet Used for pedalcyclists. See p.23, 26 of 2010 Arizona’s Crash Report Forms Instruction Manual. (this was block 4ff)

Clearly this is often coded not according to the manual, see below for some live data e.g. from 2010. We might guess that the 10% or so that say Helmet Used probably does mean those bicyclists had helmets, and likewise probably the 35% that said None Used probably means not helmet. But the other 55% is (from the data) anybody’s’ guess.

There is likewise no place on the ACR to code for nighttime crashes whether or not a bicyclist was using required lighting equipment (a front headlight or a rear taillight/reflector).

Arizona Crash Report (11th, 12th & 13th Edition)

the helmet business was changed and made explicit. Some of these changes were in the 11th edition (I have only a draft), below is what is in the 13th Edition, Revised August 2023: here are the salient bits, with my emphasis added:

5ff ‐ Safety Devices - The restraint equipment in use by the occupant, or the helmet use by a motorcyclist, at the time of the crash.
0. Not Applicable - Use for driverless/parked vehicles or pedestrians. Do not use this code for motorcycle operators or pedalcyclists.
1. None Used - Any occupant of the motor vehicle (driver, passenger) did not use a device or in the case of a motorcycle or pedalcyclist, did not use a helmet.
5. Helmet Used - This attribute applies to helmets used by drivers and passengers of all motorized cycles (motorcycles, mopeds, minibikes, motor scooters, and all-terrain vehicles) This should also be used for non-motorists such as pedalcyclists or a pedestrian on a skateboard

So that’s that. This field shows up in the database in the person table as SafetyDevice. Although there are still hundreds of “NOT APPLICABLE” for pedalcyclists despite being explicitly wrong, per the manual. At a few hundred, there are also more UNKNOWNS thank I would like to see. There are also a couple dozen apparent oddballs like seat belts, even one airbag(!). See comment below for sample data dump from 2010 and 2024.

SELECT SafetyDevice, eSafetyDevice, count(*) FROM 2021_person
WHERE ePersonType LIKE 'PEDAL%' GROUP BY 1, 2 ORDER BY SafetyDevice;

I didn’t check into the other issue regarding lighting, there’s some other fields, but only in the fatal suppleement regarding non-occupant safety devices: things like reflective clothing, lights; in any event that doesn’t get captured into the (state) database, though it presumably gets passed along into FARS.

FARS

For 1994 through 2009; all persons including bicyclists and other pedalcyclists used the P10 Restraint/Helmet Use field. The column was called REST_USE in the person table.

From 2010 and later, this info was moved to a whole new dataset, the SafetyEq table. the column name is MSAFEQMT; and it’s slightly annoying because it’s indexed by ST_CASE (i.e. the case number), and person number. There can be any number of records for any given person.

The field is called NM13 Non-Motorist Safety Equipment “This element indicates the safety equipment that was used by the non-motorist
involved in the crash”, in the FAR Manual. In the FAR Validation Manual, there’s an elaborate confusing explanation of differentiating between Not Reported and Unknown. Allowable values are:

1. None
2. Helmet
3. Reflective Clothing (jacket, backpack, etc.)
4. Protective Pads Used (elbows, knees, shins, etc.)
5. Lighting
6. (not used)
7. Other Safety Equipment
8. Not Reported
9. Unknown if Used

For reference, you can see mmucc.us‘s field P23 Non-Motorist Safety Equipment from (MMUCC is a nhtsa-funded group that sets standards for data collection on traffic crash reports). This is consistent with FARS definition; except that mmucc says only two may be selected for any person, and FARS allows any number to be selected (theoretically, the vast majority have either one or two selected).