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Home My WebLink AboutITD REQUIREMENTS - Cox, Dowanna - 355.5 W 2nd S - CUP for dorm. in MDRJUL 02 2002 11:56 RM FR CONSTRUCTION 208 334 4440 TO 912083593022 IDAHO TRANSPORTATION DEPARTMENT P.O. BOX 7129 BOISE, ID 83707-1129 FAX: (208) 334-4440 RAIL -HIGHWAY SAFETY FAX COVER SHEET To: Kert Ribbert Fax No.: 208/359-3022 From: Lee Wilson Subject: Rail -Highway Sight Triangle P.01 Organization: City of Rexburg Date Sent: 01/10/02 No. Pages (including cover): 6 If I can be of further assistance, please give me a call at any time. Lee Phone: 208/334-8561 Fax: 208/334-4440 JUL 02 2002 11:56 AN FR CONSTRUCTION 208 334 4440 TO 912083593022 P.02 Appendix B - Sight Distance Study Procedure APPENDIX B SIGHT DIS'T'ANCE STUDY PROCEDURE 10/96 69 N m A P g 2. 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Sight Distance Study Triangle 70 10/96 JUL 02 2002 11:56 AM FR CONSTRUCTION Estimation of Approach Sight Distance 208 334 4440 TO 912083593022 P.04 Appendix B - Sight Distance Study Procedure Approach sight distance is measured from the right-hand lane (driving lane) of both highway approaches. The distance is measured from the critical point on the roadway at a distance dH from the stop bar or 15 feet from the nearest rail. This distance is a function of highway approach speed and is given in Table B-1. 'fable B-1. Determination of Approach Sight Distance Vehicle Speed Required Distance Along Highway (mph) Crossing, dH (feet) 15 100 25 175 35 280 45 415 55 575 65 765 75 975 Note: All calculated distances are rounded up to the next 5 -foot increment. Source: Reference (1) If the rail -highway intersection and the warning device(s) at the intersection can be seen from or beyond the distance dH at a drivers eye height of 3.5 feet, then the available approach sight distance is greater than or equal to the required approach sight distance, and should be so indicated on the data collection form. If the rail -highway intersection and warning device(s) at the intersection can not be seen from or beyond the distance dH at a driver eye height of 3.5 feet, then the distance at which they can be seen is determined and recorded. In this case, the available approach sight distance is less than the required sight distance, and should be so indicated on the data collection form. Estimation of Quadrant Sight Distance The critical point on the highway at a distance dH from the stop bar or 15 feet from the nearest rail is determined in Estimation of Approach Sight Distance. The critical point along the tracks at a distance dr from the highway centerline is determined. This distance is a function of highway approach speed and maximum train operating speed, and is determined from Table 13- 2. 10/96 71 JUL 02 2002 11:56 RM FR CONSTRUCTION 208 334 4440 TO 912063593022 Appendix B - Sight Distance Study Procedure Table B-2. Determination of Quadrant Sight Distance, dT Vehicle speed (mph) Train Speed 15 25 35 45 55 65 75 (mph) 10 145 100 100 110 120 130 140 20 230 200 205 220 235 260 280 30 350 300 305 325 355 390 420 40 465 400 405 435 475 520 560 50 580 505 510 545 590 650 700 60 700 605 610 655 710 775 840 70 810 705 710 765 825 905 980 80 930 805 815 870 945 1,035 1115 90 1045 905 915 980 1,065 1,165 1255 Note.- All calculated distances rounded up to the next 5 -foot increment. Source: Reference W If the critical point along the tracks from the highway centerline (dT), can be seen from the critical point along the highway dH, then the available quadrant sight distance is equal to or greater than the required quadrant sight distance, and should be so recorded on the data collection form. If the critical point along the tracks from the highway centerline (dr), cannot be seen from the critical point along the highway (dH), then the distance along the highway at which dr is just visible should be determined and recorded. In this case the available quadrant sight distance is less than the required quadrant sight distance, and should be so indicated on the data collection form. Estimation of Track Sight Distance The sight distance down the track from a stopped vehicle at the crossing, the track sight distance, is measured for each direction down the track on both highway approaches. The distance (dT) to the critical point on the track is determined from Table B-3. Note that the vehicle speed is zero miles per hour for all cases, since the vehicle is stopped at the crossing. 72 10/96 ME JUL 02 2002 11:56 RM FR CONSTRUCTION 208 334 4440 TO 912083593022 P.06 Appendix B - Sight Distance Study Procedure Table B-3. Determination of Track sight Distance, dT Train Speed Distance Along Railroad From (mph) Crossing, dT (feet) 10 240 20 480 30 720 40 960 50 1,200 60 1,440 70 1,680 s0 1,920 90 2,160 Note. All calculated distances rounded up to the next 5 -foot increment. Source: Reference (1) If an individual standing at the stop bar, or 15 feet from the crossing if a stop bar is not marked, can be seen from the critical point on the tracks WA then the available track sight distance equals or exceeds the required track sight distance, and should be so recorded on the data collection form_ If, however, the individual cannot be seen from the critical point, then the available track sight distance is determined by locating the point along the tracks from which an individual at the stop bar can be seen. This available track sight distance is then recorded. 10/96 73 ** TOTAL PAGE.06 **