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OCR for page 49
49 At 10 of the sites, crashes were reduced or remained constant. incremental roadside safety improvement on their urban cor- At nine additional sites, three of the four crash trends were ridors. The research suggests the following: reduced or remained similar during the "after" period. This results in 19 of the 27 sites having a general trend of crash re- Avoid locating rigid obstacles in close proximity to a curb duction. None of the sites exhibited an increase in all four face or lane edge (at curb locations where it is possible, in- crash trend statistics, and only five sites exhibited an increase crease the lateral offset to rigid objects to 1.8 m [6 ft] from in three of the four crash trends evaluated. As a result, specific the face of the curb and do not allow the distance of this case study assessments (see Table 22 and Appendix B) pro- offset to be less than 1.2 m [4 ft]); vided inconclusive results and should be used simply as indi- Restrict the placement of rigid objects at lane merge loca- cators of the expected outcomes for similar improvement tions (avoid placing rigid objects within 3.0 m (10 ft) lon- projects. gitudinally of the taper point, which will provide a 6.1-m (20-ft), object-free length); Maintain offsets at selected higher speed auxiliary lane General Recommendations locations, such as extended-length, right-turn lanes (main- The use of corridor video analysis combined with historic tain the lateral offset from the curb face at these locations); crash statistics provided meaningful insight into urban road- Maintain careful object placement within the sidewalk side crash conditions and locations where roadside objects buffer treatment (avoid rigid objects in buffers 0.9 m (3 ft) should not be located, if possible. Conversely, the use of in width or less and strategically position objects in wider roadside improvement or beautification case studies did not buffers); and directly help to address specific roadside safety issues, but Avoid placing rigid objects in the proximity of driveways these case studies can be used by an agency proposing similar (avoid placing rigid objects on the immediate far side of the projects to determine expected overall safety performance of driveway and do not place any objects within the required these improvements. sight triangle for the driveway). This research clearly shows that there are specific locations prone to roadside crashes where agencies should avoid the In addition, roadside crashes occurred frequently at inter- placement of rigid objects. For jurisdictions with limited sections; at unique configurations (e.g., a one-way lane split at roadside safety improvement funds, urban control zones can an underpass); and known hazardous roadside conditions, such be used to help agencies establish spending priorities for as roadside ditches, non-traversable headways, and so forth.