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26 distance shown in Table 3B-1 of the MUTCD for the pre- Wyoming vailing speed. 280 ft for a speed limit of 25 mph The design standards for seven agencies (ID, IL, IN, MN, 320 ft for a speed limit of 30 mph OH, WI, and WY) specified the minimum length of a pass- 370 ft for a speed limit of 35 mph ing zone to be a range of distances based on the speed of 410 ft for a speed limit of 40 mph traffic. 500 ft for a speed limit of 45 mph 550 ft for a speed limit of 50 mph The following are the minimum lengths of passing zones 650 ft for a speed limit of 55 mph for the seven agencies that show a range of distances: 700 ft for a speed limit of 60 mph 850 ft for speed limits of 65 mph or more. Idaho 400 ft for speed limits of 45 mph or less MINIMUM LENGTH OF NO-PASSING ZONES 450 ft for a speed limit of 50 mph 2003 MUTCD Provisions 500 ft for a speed limit of 55 mph 550 ft for a speed limit of 60 mph The MUTCD does not specify the minimum length of a no- 600 ft for a speed limit of 65 mph. passing zone. Illinois Minimum Length of No-Passing Zones 400 ft for speeds of less than 60 mph and 600 ft for speeds (14 agencies) of 60 mph or more If the gap between consecutive no-passing zones is The design standards for Idaho show 250 ft as the minimum between 600 and 800 ft, connecting the no-passing length of a no-passing zone. zones is optional. The design standards for 12 agencies (AL, AK, IL, IN, IA, Indiana NY, MN, MT, OH, OR, WI, and WY) show 500 ft as the minimum length of a no-passing zone. 420 ft for a speed limit of 30 mph 480 ft for speed limits of 35 or 40 mph The design standards for Tucson/Pima County show 550 ft 530 ft for a speed limit of 45 mph as the minimum length of a no-passing zone. 580 ft for a speed limit of 50 mph 730 ft for a speed limit of 55 mph TWO-WAY LEFT-TURN LANES 860 ft for a speed limit of 60 mph 1,000 ft for a speed limit of 65 mph 2003 MUTCD Provisions (All of these dimensions are shown in metric units in the design standards.) Paragraph 3 of Section 3B.03 contains the following stan- dard: "If a two-way left-turn lane [2WLTLS] that is never Minnesota operated as a reversible lane is used, the lane line pavement markings on each side of the two-way left-turn lane shall 500 ft for 85th percentile speeds of 20 to 39 mph consist of a normal broken yellow line and a normal solid 650 ft for 85th percentile speeds of 40 to 54 mph yellow line to delineate the edges of a lane that can be used 800 ft for 85th percentile speeds of 55 mph or more. by traffic in either direction as part of a left-turn maneuver. These markings shall be placed with the broken line toward Ohio the two-way left-turn lane and the solid line toward the adja- cent traffic lane as shown in Figure 3B-7" (see Appendix A 400 ft for speeds of less than 50 mph and 600 ft for speeds for figures). This lane line standard is universally followed, of 50 mph or more. but no standards are given as to the use or placement of turn arrows in the two-way left-turn lane. Wisconsin Figure 3B-7 shows an example of the pavement markings 528 ft for speed limits of 40 mph or less that are used for 2WLTLs. The lane lines on both sides of the 686 ft for speed limits of 45 or 50 mph 2WLTL are shown as a solid yellow line adjacent to the 792 ft for a speed limit of 55 mph through lane and a broken yellow line adjacent to the 2WLTL. (These dimensions are shown as 0.10, 0.13, and 0.15 mi The typical spacing between the tips of the arrowheads of the in the design standards.) two opposing left-turn arrows that comprise a set of arrows

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27 is shown as 8 to 16 ft. The use of left-turn arrows in the 2WLTL MS, NC--10 ft is shown as being optional. FL--12 ft OK, KS--16 ft Paragraph 23 of Section 3B.19 contains the following MD--typically 16 ft support: "Lane-use arrow markings are often used to provide GA--25 ft guidance . . . in two-way left-turn lanes (see Figure 3B-7)." AR, WI--32 ft AL, AZ, TN, WV--typically 32 ft. Lane Lines (37 agencies) Minimum Spacing from One Set of Arrows All of the design standards consistently show the lane lines to the Next Set of Arrows (10 agencies) on both sides of the 2WLTL as a solid yellow line adjacent to the through lane and a broken yellow line adjacent to the The design standards for five agencies specify the minimum 2WLTL. None of the design standards show the use of lane spacing between sets of arrows as the distance between the lines that are different from those shown in Figure 3B-7 of center points of the sets. The minimum distances specified the MUTCD. for these five agencies are as follows: CLT--100 ft Use Versus Non-Use of Left-Turn Arrows TX--150 ft (37 agencies) OR--250 ft IN--400 ft Except for four agencies, the design standards consistently AR--500 ft in urban areas and 1,300 ft in rural areas. require the use of left-turn arrows in 2WLTLs. The design standards for four agencies (AZ, CA, TX, and UT) state that The design standards for two agencies specify the mini- the use of the arrows is optional. mum spacing between sets of arrows as the distance between the closest points (bottom of the arrows) of each set. The Spacing Between Opposing Left-Turn Arrows minimum distances specified for these two agencies are as in a Set of Arrows (36 agencies) follows: The design standards for 21 agencies specify the spacing AL--200 ft between opposing left-turn arrows in a set of arrows as the MI--300 ft. distance between the tips of the arrowheads. The distances specified for these 21 agencies are as follows: The design standards for one agency specify the minimum spacing between sets of arrows as the distance between the WA--5 to 10 ft tips of the arrowheads of nearest arrows. The minimum dis- NH--8 ft tance specified for this agency is as follows: MN, NV, OH, PA--8 to 16 ft TX--typically 8 to 16 ft UT--100 ft. MT--no less than 10 ft and no more than 20 ft CLT--15 ft The design standards for two agencies specify the mini- SD--16 ft mum spacing between sets of arrows, but do not indicate how ID--18 to 32 ft depending on the prevailing speed the distance is measured. The minimum distances specified NE--24 to 32 ft in urban areas and 32 to 40 ft in rural for these two agencies are as follows: areas MI--32 ft IL--200 ft CO, DE, IN, IA, LA, WY--typically 32 ft OH--500 ft for speeds of 40 mph or less and 1,000 ft for UT--typically 33 ft speeds of more than 40 mph. CA--generally equal to the left-turn arrow size (the typ- ical left-turn arrow is 8 ft long, but an arrow that is 24 Maximum Spacing from One Set of Arrows ft long may be used on high-speed roadways). to the Next Set of Arrows (14 agencies) The design standards for 15 agencies specify the spacing The design standards for six agencies specify the maximum between opposing left-turn arrows in a set of arrows as the spacing between sets of arrows as the distance between the distance between the closest points of the arrows. The dis- center points of the sets. The maximum distances specified tances specified for these 15 agencies are as follows: for these six agencies are as follows: NY--5 ft MN--200 ft OR--typically 8 to 16 ft CLT--300 ft

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28 ID--300 ft if the average daily traffic (ADT) is more than AL--400 ft 10,000 and 500 ft if the ADT is less than 10,000 MD--typically 800 ft. WA--500 ft AR--1,000 ft in urban areas and 1,500 ft in rural areas The design standards for one agency specify the desired TX--1,500 ft. or required spacing between sets of arrows, but do not indi- cate how the distance is measured. The desired or required The design standards for one agency specify the maxi- distances specified for this agency are as follows: mum spacing between sets of arrows as the distance between the closest points (bottom of the arrows) of each set. The MT--500 ft in urban areas and 1,320 ft in rural areas. maximum distance specified for this agency is as follows: MI--1,000 ft. Other Considerations Regarding the Spacing of Sets of Arrows (15 agencies) The design standards for one agency specify the maxi- The design standards for New York recommend that a set mum spacing between sets of arrows as the distance between of arrows be placed 21 ft (shown as 6.5 m) from the end of a the tips of the arrowheads of the nearest arrows. The maxi- single-direction turn lane (this distance is measured from the mum distance specified for this agency is as follows: bottom of the nearest arrow to the end of the 2WLTL). UT--300 ft. The design standards for the city of Charlotte show that a set of arrows is placed 25 ft from the end of a single-direction The design standards for six agencies specify the maxi- turn lane (this distance is measured from the center point be- mum spacing between sets of arrows, but do not indicate how tween a pair of arrows to the end of the 2WLTL). the distance is measured. The maximum distances specified for these six agencies are as follows: The design standards for Oklahoma show that a set of FL, IL--300 ft arrows is placed 30 ft from the ends of the 2WLTLs, includ- WI--400 ft ing when they are interrupted for intersecting streets. LA--750 ft OH--1,000 ft for speeds of 40 mph or less and 1,500 ft The design standards for Idaho show that a set of arrows for speeds of more than 40 mph should be placed such that the tip of the nearest arrowhead is TN--2,640 ft (shown as a half-mile). no closer than 50 ft to the nearest edge of an intersecting street. The design standards for Maryland require that a set of Spacing from One Set of Arrows to the arrows be placed on each approach to all intersecting streets Next Set of Arrows (12 agencies) at a distance of 50 ft from the resumption of the centerline markings. The design standards for seven agencies specify the desired or required spacing between sets of arrows as the distance The design standards for Minnesota recommend that a set between the center points of the sets. The desired or required distances specified for these six agencies are as follows: of arrows be placed such that the center point between a set of arrows is 50 ft from the resumption of the centerline mark- WV--typically 200 to 500 ft ings if they are interrupted for an intersecting street. MS--250 ft NC, PA--typically 320 ft The design standards for Montana require that a set of OR--placed at even intervals, proportioned within each arrows be placed 50 ft from intersections or the ends of single- block, with the approximate interval in feet being ten direction turn lanes. times the posted speed limit in mph IA--the interval in feet is typically ten times the speed The design standards for Mississippi require that each limit in mph, or one set of arrows located midblock segment of continuous 2WLTL be considered separately. If KS--the interval in feet is ten times the speed limit in mph. the segment is shorter than 350 ft, one set of arrows is placed in the center of the segment. If the segment is longer than The design standards for four agencies specify the desired 350 ft, the first set of arrows is placed 50 to 100 ft from the or required spacing between sets of arrows as the distance beginning or end of the segment. between the closest points (bottom of the arrows) of each set. The desired or required distances specified for these four The design standards for New Hampshire recommend agencies are as follows: that a set of arrows be placed no less than 50 ft and no more than 100 ft from the end of a single-direction turn lane (this OK--200 ft distance is measured from the tip of the nearest arrowhead to NY--typically 200 ft the end of the 2WLTL).