Perceptions may have been altered

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By Patricia Max

During at least two public meetings where several designs of Trinity were proposed, the contractor, MIG, displayed a graph and explained that it showed how dangerous Trinity Drive is.
That graph represented data found in a document entitled Environmental Assessment New Mexico 502 Improvement Project: Knecht Street to Tewa Loop Los Alamos County, New Mexico.  
The lead agencies were the Federal Highway Administration and New Mexico Department of Transportation. The graph purported to show that there are 528 accidents per million vehicle miles in the 8/10 of a mile between Tewa and Knecht. Using the traffic count of about 15,000 cars daily between those two streets, it is easy to calculate that it would take about 90 days to travel a million vehicle miles. That means there are 528 accidents every 90 days or so or 2,112 accidents per year between Tewa and Knecht. The data really represented 528 accidents per 100 million vehicle miles but was typed incorrectly in the state assessment.
Using the same traffic count, it would take about 24 years to travel 100 million vehicle miles between Tewa and Knecht, resulting in about 2.2 accidents per year.  
Companies that make a living using accident data as a basis for street design should verify the data they use to generate designs and to perform traffic simulations.
In the fall of 1995, the council approved widening Trinity to five lanes because the council decided that Trinity was not only an access road to businesses, but also a major arterial.
There was discussion at that time that 20th Street and Trinity warranted a stop light, but it was never installed.  There are serious problems with NM502/East Road/Trinity.  There are safety issues for those who pull in and out of East Park Pool.
There should be more pedestrian crossings between 20th and Diamond. Pedestrians need safe sidewalks separated from the traffic. Bicyclists need a safe lane.
However, today there are more commuters on Trinity than there were 15 years ago. During the last seven years or so, the council has been very focused on developing the south side of Trinity.  They expect that those spending money at Trinity Place are not just Los Alamos County residents, but also are those who commute to Los Alamos to work.  
The 15,000 cars counted between Tewa and Knecht, did not come just from the Eastern Area. Many belong to commuters who either work north of the bridge, in the downtown, or are bringing their children to school before crossing the bridge.
Perceptions might have been altered by the presentation of invalid data. Certainly Trinity, the state highway and the heavily used commuter route, has been minimized.  
What’s really astounding is that as more and more accident data is analyzed, one learns that Central Avenue, two lanes, 25 mph, with probably less than 1/4 of the Trinity traffic, has had almost the same number of accidents as Trinity, five lane, 35 mph over the same time period.  
Council has two options — continue design of a two lane road with roundabouts and force commuter traffic to the truck route or Canyon Road and away from the retail along Central and Trinity, or acknowledge the multiple reasons motorists use Trinity, the false perceptions caused by the invalid data, and the design that does not support the goals of increasing shopping in Los Alamos.

Patricia Max
Los Alamos


Good points; one oops

I agree with much of what you have written. However, there's a numerical mistake in your accident accounting. Skip the slight (!) error on NM's and MIG's part of claiming that the rate was measured in per million miles instead of per 100M miles [they only missed that part by a factor of 100 :-)]. Use the 100M number. I get 23 years instead of 24. Not a big deal-- we essentially agree on that. However, 528 accidents in 23 years comes to 23 accidents per year, not 2.2. OK, so you slipped a factor of 10 -- but, we didn't pay you $300K to redesign our roadway, so your mistake is less of a gaff than the two (what?) by the pros.

That brings me to the second issue with the "professional" result that MIG showed. This stretch of road does NOT have 23 accidents per year. It is more like 6/year according to accident data for 2008-2009 compiled by the University of New Mexico. MIG seems to have accepted data from a NM 2007 report without checking it further for applicability?

One can bypass all the calculations and compare accident counts directly. Trinity's number of accidents in 2008-2009 in the segment between Oppenheimer Drive to the junction of Central Ave. and Trinity is the same as that for Central Avenue.

Your main point stands by either test: Trinity is safe.

Please take a look at the NM502 information on my website at www.wcmead.org for more info about the NM502 proposed changes. I think there are many more errors or misjudgments than those mentioned here.

William Mead