依據道路交通事故資料分析，公路施工區路段的交通事故主因係為駕駛人超速和疏忽所引起。然而由於施工區路段路幅寛度的限縮，增加了警車攔停取締違規超速勤務的困難度與危險性。為了能有效遏止施工區路段車輛違規超速情形，美國伊利諾州政府立法允許執法單位於道路施工區路段，使用自動測速照相取締超速違規，其測試使用的行車管制策略包括：(I)車輛速率偵測與顯示標誌；(II)警車駐守（不執行取締）；(III)自動測速照相車輛；(IV)前述(I)和(II)組合。測試結果發現，除了單獨使用速率顯示標誌策略外，其它策略均可明顯降低管制路段上的行車速率約4-8 英哩/小時（6.4-12.9公里/小時）於一般車輛平均速率，及3-7 英哩/小時（4.8-11.3公里/小時）的大貨車平均速率，亦可降低車輛違規超速的比率。對於整體施工路段的行車速率，則以採自動測速照相策略時，有顯著影響，並降低車輛違規超速的比率，其中又以對大貨車的影響最為顯著，對於提升整體施工路段的行車安全，有顯著的效果。

According to traffic crash data analysis, speeding and driver distraction are the major contributors for traffic crashes at highway work zones. Due to the width limitation of road shoulders, implementation of personal enforcements at work zones becomes a risking and challenging task. To improve work zone safety and increase speed limit compliance, the Illinois Department of Transportation implemented automated speed photo–radar enforcement (SPE) in work zones for the first time in the United States. This paper presents the field evaluations of the SPE along with other speeding management devices and strategies being used, such as (I) speed active sign trailer; (II) police present; (III) automatic speed photo-radar enforcement; (IV) combination of the trailer and the police car, in two work zones. The results showed that near the SPE locations, speeds of free-flowing cars were reduced by 4 to 8 mph [6.4-12.9Km/Hr]and free-flowing heavy vehicles by 3 to 7 mph[4.8-11.3Km/Hr]. The cumulative percentile of the speed distributions showed that the implementation of the SPE can also reduce the percentage of speeding and narrow the dispersion ranges of the speed distributions. Particularly for heavy vehicles, the speed reductions were still significant at the 1.5 kilometers。downstream from the speed management location. This finding indicates the effectiveness of the SPE on speed reduction and traffic safety was not only limited at the speed management segments, but also extended for the entire segments along the work zones.