[Summit] Fw: Enhanced Speed Limit Enforcement

Thu Mar 8 20:42:30 UTC 2018

"""
"But the fines are effective as a tool to slow folks down.  Once a neighbor
gets a fine, the whole neighborhood knows to slow the hell down."

Is there data to back this up, or is it just a gut feeling? I thought
Mikaila presented a pretty good argument that this isn't true, and why
other methods are actually superior.
"""

There are lots of scholarly studies and research available on this topic.
Here's a sampling of search results:
https://scholar.google.com/scholar?as_ylo=2017&q=speed+camera+traffic+effect&hl=de&as_sdt=0,31

I chose a few results at random from several sources and examined the
abstracts. Links and excerpts are given below.
*For those who want the executive summary, I pulled five papers, four of
which supported the conclusion that speed cameras (not red light cameras)
reduce speeding and/or injuries. That fifth study appears to be
inconclusive as to whether the cameras served to modify behavior.*

https://doi.org/10.1136/bmj.38324.646574.AE : "Conclusions: Existing
research consistently shows that speed cameras are an effective
intervention in reducing road traffic collisions and related casualties.
The level of evidence is relatively poor, however, as most studies did not
have satisfactory comparison groups or adequate control for potential
confounders. Controlled introduction of speed cameras with careful data
collection may offer improved evidence of their effectiveness in the
future."

https://arxiv.org/abs/1703.05926: "This paper quantifies the effect of
speed cameras on road traffic collisions using an approximate Bayesian
doubly-robust (DR) causal inference estimation method. Previous empirical
work on this topic, which shows a diverse range of estimated effects, is
based largely on outcome regression (OR) models using the Empirical Bayes
approach or on simple before and after comparisons. Issues of causality and
confounding have received little formal attention. A causal DR approach
combines propensity score (PS) and OR models to give an average treatment
effect (ATE) estimator that is consistent and asymptotically normal under
correct specification of either of the two component models. We develop
this approach within a novel approximate Bayesian framework to derive
posterior predictive distributions for the ATE of speed cameras on road
traffic collisions. Our results for England indicate significant reductions
in the number of collisions at speed cameras sites (mean ATE = -30%). Our
proposed method offers a promising approach for evaluation of transport
safety interventions. "

https://www.sciencedirect.com/science/article/abs/pii/S1369847816301632 :
"The purpose of this paper is to describe the results obtained from
analysis of probe vehicle data on the effect of speed enforcement cameras
that were installed at non-urban roads in Israel during 2011–2013. In
addition to the contribution regarding the impact of enforcement cameras,
the paper demonstrates the potential (as well as the challenges) of using
probe vehicle data for safety studies. The analyses in this paper consider
22 installation sites and 12 comparison sites. The results show that at the
installation sites (within 100 m), the 85th percentile speeds exhibited a
short-term (two months) reduction of 2.92 km/h (SD = 2.37) and a long-term
(one year) reduction of 6.48 km/h (SD = 3.5). An a-symmetric double
exponential model is presented to depict the halo effect up to 1.5 km from
the installation location."

http://injuryprevention.bmj.com/content/9/4/302.short : "Results: Camera
sites had lower than expected numbers of injurious crashes up to 300 metres
using circles and up to 500 metres using routes. Routes methods indicated a
larger effect than the circles method except in the 100 metres nearest
sites. A 500 metre route method was used to investigate the effect within
strata of time after intervention, time of day, speed limit, and type of
road user injured. The number of injurious crashes after intervention was
substantially reduced (rate ratio 0.49, 95% confidence interval 0.42 to
0.57) and sustained throughout two years after intervention. Significant
decreases occurred in daytime and night time, on roads with speed limits of
30 and 60–70 miles/hour and for crashes that injured pedestrians,
motorcycle users, and car occupants."

https://www.sciencedirect.com/science/article/abs/pii/S0001457517302981 :
"Fixed and mobile speed cameras are an important element of enforcement
initiatives designed to create a strong deterrent effect and improve road
safety. Despite the widespread use of the technology and the need to create
a strong deterrent effect, research has yet to determine if there is a
relationship between levels of exposure to the devices and subsequent
self-reported deterrent effects. As a result, licensed motorists (*N* = 536;
51% female) in Queensland (Australia) were recruited to complete a
questionnaire that measured exposure to speed cameras and associated
offending behaviours. Data were analyzed utilising descriptive, bivariate
and multivariate statistics. The key findings that emerged were: the sample
reported a higher level of exposure to fixed cameras (even though there are
more operational mobile cameras), younger males were most likely to speed
and be observant of speed cameras and that perceived certainty of
apprehension was the largest reported deterrent force. However, a positive
(rather than negative) relationship was found between perceived camera
exposure levels and speeding behaviours, which indicates a range of
additional factors (both legal and non-legal factors as well as driving
exposure levels) influence speed limit non-compliance. Furthermore,
multivariate analysis revealed that higher levels of perceptual certainty
were associated with general speed compliance and perceptions of the
severity and swiftness of sanctions, rather than levels of self-reported
camera exposure. This paper is the first to reveal that while motorists
prone to speed may be more cognisant of speed camera operations, this in
itself does not ensure appropriate behaviour modification."

Mark Fuller
324 Rochambeau Ave.
Providence, RI 02906
+1 732-513-7119
+49 (0)1577-1848188
mark.e.fuller at gmail.com

2018-03-08 15:13 GMT-05:00 Christopher Buecheler <cwbuecheler at gmail.com>:

> "But the fines are effective as a tool to slow folks down.  Once a
> neighbor gets a fine, the whole neighborhood knows to slow the hell down."
>
> Is there data to back this up, or is it just a gut feeling? I thought
> Mikaila presented a pretty good argument that this isn't true, and why
> other methods are actually superior.
>
> I'm with you on Rhode Island drivers though.
>
>
> --
> -Christopher Buecheler - @cwbuecheler
> -http://cwbuecheler.com | Web, Writing, Cocktails and More
>
> _______________________________________________
> Summit mailing list
> Summit at sna.providence.ri.us
> http://sna.providence.ri.us/mailman/listinfo/summit_sna.providence.ri.us
> SNA Website: http://sna.providence.ri.us/
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sna.providence.ri.us/pipermail/summit_sna.providence.ri.us/attachments/20180308/00e2a51d/attachment.htm>