2001-03-19 Special Called Regular Meeting and Public Hearing

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e C~ 6 / Access and S;te Circ(J) =r~ I 'I 156 Paint stripe, 14 inches, yellow 11'3 11'2 RI ~L' WI ~L3-1 L.--1 Approach geometry (feet) Departure geometry (feet) all speeds R! L3 a Arterial speed (mph) LI L a W1b II' C RI 2 2 45 desirabled 120. 250. limiting" 10.0. 130. r 16 20. 40. desirable 120. 190. f 12 18 15 limiting 90. 10.0. 12 20. 10. 35 desirable 90. 120. limiting 60. 60. If C 3 14 16 16 15 10 15 a 5 5 a 20. 20. I, , a. .. a Maneuver distance only: does not include storage for more than one vehicle. b Excluding curb and gutter, C Stripe to back of curb. d 1 a mph speed differential, 7 fps2 average maximum deceleration. '15 mph speed differential. 9 fps! average maximum deceleration. f Any set of L I L! values may be used with any set of 1I'!II'2R I val ues. I, '. ;.: -- ..' ., . ~'L ' ... .~l~ '.,: '. . >1:" t.' t .~l . ~. .. to.:' Fig~re 6-2 Suggested design for undivided driveway access to arterial streets. SOURCE: Vergil G. Stover [2]. Where the driveway spacing is less than that necessary to accommodate a right-turn deceleration lane (Figure 6-4) and stilI have substantial lengths of curb between successive driveways, a continuous right-turn lane should be considered (Figure 6-5). Any continuous right-turn lane should tenninate at signalized intersections. The termination should be accomplished by a channelizing island which forces all traffic in the lane to turn right at the intersection. Whenever a channelizing island is used at the tenninus of a right-turn bay or lane, the inside curb return radius should be a minimum of 75 feet. This will provide an island of sufficient size to allow for landscaping and enhanced visibility. The absolute minimum radius necessary to provide for an island of minimum legal size is 50 feet. Designs to Restrict Certain Movements " In some instances, it is desirable to prohibit certain movements through the use of channelizing islands (Figure 6-6). Signing and pavement markings are not effective in eliminating prohibited movements. The geometry must physically define and block the movements which are prohibited. Use of a channelizing island which prohibits left turns in and out (Figure 6-6) is suggested on arterials without a median and on one-way streets, The installation of supplementary one-way drives reduces the number of turning vehicles at a T-intersection on a divided arterial having a barrier median (Figure 6-7). The supplementary drives might be installed to serve egress or ingress maneuvers or both.