Study Details
Study Title: Safety Evaluation of an Automated Section Speed Enforcement System
Authors: Montella et al.
Publication Date:JAN, 2012
Abstract: Speeding is among the most significant contributing factors to fatal crashes, so most road agencies attempt to achieve the right operating speed among drivers by imposing speed limits.
Unfortunately, there tends to be a high prevalence of speed limit violations, even on motorways with speed cameras. Part of the problem with speed camera enforcement is that some motorists brake before passing a camera location and then speed up to above the speed limit after they have passed it. This sudden braking can cause dangerous situations, crashes, or tailbacks. Furthermore, a safe operating speed is not achieved where there are no cameras, especially where the enforcement is overt, as is the case in Italy. A new technique to overcome these problems is the Automated Section Speed Enforcement System (ASSES). Unlike conventional speed meters, which measure the speed of a vehicle at one point, ASSESs determine the average speed over a long distance.
The objective of this study was to evaluate the safety effectiveness of the ASSES installed on the Italian Motorway A1 Milan-Naples in the 2007. An empirical Bayes observational before-after study was performed. The estimate of the total crash reduction is 31.2%, with a lower 95% confidence limit of 24.3%. The greatest crash reductions were observed for severe crashes and crashes at curves. The reduction was 55.6% for severe crashes, 26.6% for non-severe crashes, 43.4% at curves, and 28.4% at tangents. However, it is worthwhile to observe that the effectiveness decreased over time. The crash reduction was 39.4% in the first semester after the system activation while it was 18.7% in the fifth semester.
Overall, the study results strongly support the activation of the ASSES because of the highly significant and substantial safety effects. On the other hand, it is stressed that the system effectiveness decreases over time, a situation that may be correctible with higher levels of enforcement.
Study Citation: Montella, A., Persuad, B., D'Apuzzo, M., Imbriani, L., "Safety Evaluation of an Automated Section Speed Enforcement System." Presented at the 91st Annual Meeting of the Transportation Research Board, Paper No. 12-0226, Washington, D.C., (2012)
CMFs Associated With This Study
Category: Advanced technology and ITS
Countermeasure: Install automated section speed enforcement system
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.69 | 31 |  | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.82 | 18 | | Run off road | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.86 | 14 | | Rear end | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.52 | 48 | | Sideswipe | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.62 | 38 | | Not specified | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.74 | 26 | | Day time | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.62 | 38 | | Nighttime | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.69 | 31 | | Dry weather | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.69 | 31 | | Wet road | All | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.73 | 27 | | All | B,O | Principal Arterial Other Freeways and Expressways | Not specified |
| 0.44 | 56 | | All | K,A | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Install automated section speed enforcement system on curves
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.57 | 43 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Install automated section speed enforcement system on tangents
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.72 | 28 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Temporal effects of automated section speed enforcement system - 12 months
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.66 | 34 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Temporal effects of automated section speed enforcement system - 18 months
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.68 | 32 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Temporal effects of automated section speed enforcement system - 24 months
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.69 | 31 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Temporal effects of automated section speed enforcement system - 30 months
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.81 | 19 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
Countermeasure: Temporal effects of automated section speed enforcement system - 6 months
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|
| 0.61 | 39 | | All | All | Principal Arterial Other Freeways and Expressways | Not specified |
