Thursday, March 7, 2019

Red Light Camera Enforcement Reporting Looks Odd

Over at CANDO they recently posted a link to a report to the Legislature on Salem's three red light cameras, violations, and the tickets they generate.

Is it possible that there's 3x as much traffic in 2018 as 2012?
That would be more than 67% increase!

Just in general this does not look like very reliable data
It looks very much like the data needs to be scrubbed more, however. It's hard to believe the numbers as reported.

By comparison, here are the numbers the Congestion Relief Task Force used. They show a much different pattern, nothing like a jump from 7.9 million to 23.4 million between 2012 and 2018. An increase similar to what is shown on the bridges would be more like from 8 million to 9 million.

From the Congestion Relief Task Force
Other than wanting the best, most accurate data, I don't know how any errors specifically might matter to revenue, cost, staffing, or anything else. But the City and Police should consider a closer look, maybe even a kind of audit, for the Red Light Camera numbers. They look funny. And to try to draw any conclusions from them seems very premature.

1 comment:

Evan said...

Serious maths problems here.

The % in the chart are two factors off - % to volume is 0.043%, for example, not 4.3% (for the 4,033 vs 23 million).