5Harwood D W, Hoban C J. Low cost methods forimproving traffic operations on two lane roads:information guidefS]. Federal Highway Administration.U.S. Department of Transportation. Washington. D.C.1987.
6Morrall John, Miller Jr Edward, Smith Geraid A, et al.Planning and design of passing lanes using simulationmodel[J]. Journal of Transportation Engineering, 1995,121:50-62.
7Persaud Bhagwant, Lyon Craig, Bagdade Jeffrey, et al.Evaluation of the safety performance of passing relieflanes[J]. Transportation Research Record. 2013:58-63.
8Harwood, Douglas W. Passing lanes and otheroperational improvements on two-lane highways[J].Transportation Research Record, 1995,7:1-6.
9Harwood D W, C J Hoban, D L Warren. Effective use ofpassing lanes on two- lane highwaysfj]. TransportationResearch Record 1195, TRB, National ResearchCouncil, Washington, D.C., 1988: 79-91.
