Evaluation of Section Speed Enforcement System Using Empirical Bayes Approach and Turning Point Analysis

Table 1

Data for nine SSESs on Korean expressways.

Site ID	Route name (section ID)	Direction	Postkilometer		Distance	Speed limit	Attributes	Enforcement starting date	Analysis period	AADT		No. of crashes
			Start	End						Before	After	Before	After
1	Seohaean Expressway (I)	NB (to Seoul)	273.5	282.6	9.1 km	110 km/h	Bridge, rest area	01/15/2008	B/A 12-month	91,712	98,222	11	8
2	Seohaean Expressway (II)	SB (to Mokpo)	282.6	273.5	9.1 km	110 km/h	Bridge, rest area	01/15/2008	B/A 12-month	91,774	98,218	17	17
3	Pyeongtaek-Jecheon Expressway	WB (to Pyeongtaek)	11.2	5.5	5.7 km	100 km/h		12/24/2008	B/A 12-month	78,736	82,655	5	5
4	Yeongdong Expressway (I)	EB (to Kangnung)	168.5	176.0	7.5 km	100 km/h	Tunnel	12/26/2007	B/A 12-month	21,581	20,949	21	11
5	Yeongdong Expressway (II)	WB (to Incheon)	172.2	161.8	10.4 km	100 km/h	Tunnel	10/16/2009	B/A 33-month	58,263	59,429	54	25
6	Jungbunaeruk Expressway	(To Masan)	223.9	209.8	14.1 km	110 km/h		12/20/2008	B/A 24-month	19,051	19,612	16	17
7	Jungang Expressway	SB (to Busan)	242.8	237.2	5.6 km	100 km/h	Tunnel	02/21/2008	B/A 12-month	33,894	33,828	3	3
8	Daejeon–Tongyeong Expressway	SB (to Tongyeong)	85.5	78.0	7.5 km	100 km/h		01/01/2009	B/A 24-month	39,592	42,402	26	9
9	Yeongdong Expressway (III)	EB (to Kangnung)	215.2	226.0	10.8 km	100 km/h		12/07/2011	B/A 24-month	81,230	84,885	19	8

B/A 12-month means 12-month analysis period before-and-after installation (total 24 months).