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3. Safety Effects of Horizontal Curve and Grade Combinations on Rural Two-Lane Highways. Report No. FHWA-HRT-13-077;Bauer,2013
4. Carter, D., Srinavasan, R., Gross, F., and Council, F., 2012, Recommending Protocols for Developing Crash Modification Factors. NCHRP 20-7(314) Final Report.
5. Highway Safety Information System;HSIS,2016