Bicyclist killed in collision at College/Alameda 4-way stop

Feb 14, 2023 5:38AM College and Alameda, Tempe AZ.

A 55 y.o. male bicyclist was killed at this all way (AWSC, All Way Stop Controlled) intersection.

According to the police report, based on the driver and two independent witness statements, the northbound bicyclist failed to stop and rode into the side of a westbound driver of a F-150 pickup.

The witnesses were also northbound, were walking (or jogging) along the eastern sidewalk, approached the intersection and saw a stopped westbound F-150 at the intersection.

The bicyclist, Mark McWirtner was known to be a  regular, even daily, rider. The witness statements suggest the bicyclist may have been under the impression that the driver saw him (the bicyclist) and that was why he proceeded ahead:

“After F-150 driver made eye contact with (witness 1), the F-150 proceeded WB into the intersection”…
“(witness 1) never saw the bicyclist stop and thought the bicyclist may have thought the F-150 driver saw him”

This is a very unusual type of fatal bicyclist collision (some attempt at statistics below). It’s unique in Tempe fatal bike collisions (at least back to 2009), you can view a list of each of the dozen-or-so bicyclist fatalities in Tempe here; and in fact is unique in all of Arizona during that timeframe (though an Aug 2021 incident in Phoenix was a delayed fatality).

Particularly being at the intersection of two low-speed (25? maybe one of the other is 30?) roads.

As mentioned here, this particular intersection has been featured for targetted enforcement, despite heretofore having a nearly-perfect safety record for well over 10 years.

As an aside, when a crash occurs “light trucks” are more likely to kill those outside the vehicle, whether they are car drivers/occupants, motorcyclists, pedestrians or bicyclists. This is due to a combination of being heavier overall, along with a dangerous front-end design, along with being higher off the ground.

In this instance the bicyclist struck the front wheel area, flipped over and landed in front where he was (slowly) run over with the front wheel coming to rest on the bicyclist’s body. Cars (real cars) are less likely to run someone over; due to their front-end design. Despite these glaring “crash incompatibilities” as the industry calls it, regulators (in the US) have failed to enact any safety standards in this regard.

AWSC Statistics

The acronym AWSC stands for All-Way Stop-Controlled; compare to TWSC, two-way stop-controlled.

Well, I’ve sort of given up; it seems that there is no way to extract general statistics for AWSC intersections because both the state database, as well as the Federal (FARS) database make no distinction between a stop sign, and an all-way stop sign.

In terms of fatal MV-bicyclist crashes in Arizona, I’ve looked at each one (they are all listed here back to 2009) and this has never happened before

I did do a quick sort on “serious” (incapacitating injury) bicyclist collisions back to 2009 where both the bicyclist and motorist had a stop sign; this yielded 56 crashes (out of about 22,000 bike-MV crashes reported, about 2,600 are serious injury) — but only 22 were at 4-way stop intersections. Here is a spreadsheet (see worksheet names “4-way stop” of these crashes, in case you are interested. Several involved children. [On that list is a serious 2021 collision involving Hans Hughes with full documentation here which resulted in a delayed fatality].

Converting an intersection from TWSC (two-way) to AWSC is universally claimed to be a significant safety improvement; some references below.

Here’s the reported crashes as 4 selected AWSC intersections over the period 2009-2022 (FOURTEEN YEARS)… as you can see, there are relatively few crashes reported to begin with, and the severity — WITH THE PRESENT CASE EXCEPTED — is very low; with only one (a pedestrian) suffering an incapacitating injury.


  # MV- only crashes # of MV-ped crashes # MV-bike crashes  
College and Alameda, Tempe 11 (1 MV occupant non-incap injury) 1 (1 non-incap injury) 0
13th St and Farmer, Tempe 9 2 (1 possible; 1 incap injury) 3 (2 possible inj; 1 non-incap injury)
3rd Street and Treat Avenue, Tucson * 0 0 1 (no injury)
36th St and Knox Rd, Phoenix 8 (1 MV occupant non incap-injury) 0 0

Except as noted, the MV-only crashes resulted in either no injury, or possible injury.

*  Third and Treat in Tucson was converted to a roundabout sometime around July 2022; the stop signs were removed, and entering traffic yields to any traffic in the roundabout.





References “it is found that the full-stop rate is only 20.2% at AWSC intersections

From HSIP Calms Intersections :”As of 2020, NCDOT has used HSIP and other funds for more than 150 projects that converted two-way stop controlled intersections (TWSC) to all-way stop-controlled intersections (AWSC). A study of the first 50 projects showed a 68-percent reduction in total crashes and a 77-percent reduction in fatal and injury crashes.³ A 2020 follow-up study of 36 locations found that conversions eliminated fatal and severe injuries and reduced other crash types by 60–75 percent!

Simpson, C.L. and J.E. Hummer, “Evaluation of the Conversion from Two-Way Stop Sign Control to All-Way Stop Sign Control at 53 Locations in North Carolina.” Journal of Transportation
Safety and Security, Vol. 2, No. 3, 2010, 239-260

Query for ASDM (Arizona database)

for FARS, the unit’s VTRAFCON=20 is similar to AZ’s ControlType=2. It’s in some ways harder to extract anything relevant from FARS, would need to qualify by PBType of crash, e.g.

select count(*) from incident WHERE sF_Bicycle and InjurySeverity = 4;

select count(*) from incident WHERE sF_Bicycle ;

SELECT count(*)
FROM (((( 2016_incident AS i JOIN 2016_person AS p_bike ON i.IncidentID = p_bike.IncidentID)
JOIN 2016_unit AS u_bike ON p_bike.UnitID = u_bike.UnitID)
JOIN 2016_person AS p_car ON i.IncidentID = p_car.IncidentID)
JOIN 2016_unit AS u_car ON p_car.UnitID = u_car.UnitID )
LEFT OUTER JOIN LOVNcic AS OffNcic ON i.OfficerNcic =
LEFT OUTER JOIN LOVNcic AS ExtNcic ON i.ExtendedNcic =
WHERE p_bike.ePersonType = 'PEDALCYCLIST' AND p_car.ePersonType='DRIVER'
AND u_bike.ControlType=2 AND u_car.ControlType=2 AND p_bike.InjuryStatus IN (5)
ORDER BY i.IncidentDateTime;

Here’s an example query for a particular intersection (use sF_Pedestrian or sF_Bicycle to isolate person types, and motorists by subtraction:

SELECT SUM(TotalMotoristsFatalities), SUM(TotalNonMotoristsFatalities),
SUM(TotalMotoristsInjuries), SUM(TotalNonMotoristsInjuries)
FROM incident i LEFT OUTER JOIN LOVCity ON i.CityId = LEFT OUTER JOIN LOVCounty ON i.CountyId = WHERE ( (OnRoad LIKE "college%" AND CrossingFeature LIKE "alameda%") OR (OnRoad LIKE "alameda%" AND CrossingFeature LIKE "college%") ) AND IncidentYear IN (2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021,2022) AND LIKE "tempe%";

SELECT eInjurySeverity, count(*)
FROM incident i LEFT OUTER JOIN LOVCity ON i.CityId = LEFT OUTER JOIN LOVCounty ON i.CountyId = WHERE ( (OnRoad LIKE "college%" AND CrossingFeature LIKE "alameda%") OR (OnRoad LIKE "alameda%" AND CrossingFeature LIKE "college%") ) AND IncidentYear IN (2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020,2021,2022) AND LIKE "tempe%" GROUP BY 1;


CrashGroup / CrashType
Bicyclist Failed to Yield – Sign-Controlled Intersection

2 thoughts on “Bicyclist killed in collision at College/Alameda 4-way stop”

  1. I’ve riden through this intersection thousands of times in the past 50 years. The cyclists on College rarely stop. Motorists who drive this area know this and usually give the cyclcists a brake.

  2. And the cops have been using this as an excuse to ticket more cyclists at this intersection. I got a ticket in June and saw the same cop writing another bike a ticket there the next week. My ticket was at 7am on a Sunday, in the 10 minutes it took him to write me up, not a single car passed through the intersection.
    Cop tells me, someone on a bike was killed here a few months ago. I ask him how the driver of the car is doing, how much damage the bike did to the car?

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