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1 � .
<br /> , Feb. 8, 1983 BIKEWAYS .5.
<br /> ' IV. BIKEWAY DESIGN TABLES Desiqn Speed Desiqn Radius
<br /> mph feet
<br /> The first step in the evaluation of a proposed project 10 15
<br /> t is an analysis of the road desiqn and the volume of motor 15 35
<br /> vehicles (ADT). The followinq tables provide the desiqner 20 70
<br /> with an understandinq of his present situation and enables 25 90
<br /> him to proqress to determine desiqn options. Dependinq 30 125
<br /> ' upon the review of the service area, the probability of
<br /> project implementation, review of abutting section, and {�ere more than standard cross-slope is provided see
<br /> fundinq, the appropriate desiqn level can be determined. Fiqure A for curve radii.
<br /> ' In the tables:
<br /> — Road sections currently rated "qood" or "fair" C. SUPERELEVATION
<br /> will qenerally not be eliqible for shoulder or off-road
<br /> construction. As with curvature, superelevation on shared roadway
<br /> ' — If a suitable parallel road or off-road bikeway exists, facilities the hiqhway superelevation or shoulder slope will
<br /> funding from Mn/DOT will be denied.
<br /> — Off-road desiqn will be considered if shoulder con- 9overn and be more than adequate for cyclists.
<br /> struction cannot enhance the road to "good" or "fair" However, with off-road bikeways, some superele-
<br /> ' status. vation should be provided on all curves, .OS foot per foot
<br /> should be used as the qeneral desiqn value and.02 foot per
<br /> V. D ES 1 G N C R I T E R I A foot as the absolute minimum value (the minimum rate
<br /> , of cross slope required for drainaqe). In some cases, a
<br /> A. DESIGN SPEED rate of superelevation qreater than .OS foot per foot may
<br /> be advantaqeous; however, pedal clearance must be con-
<br /> sidered when increased super is used. A straiqht .02 foot
<br /> Curvature, superelevation, qradient and width of per foot cross slope is recommended for tanqent sections.
<br /> �traveled way are geometric features which affect the speed
<br /> at which a bicyclist can travel safely and with comfort. In D. GRADES
<br /> addition, factors such as traffic, the type of bicycle, physi-
<br /> ' cal condition of the rider, wind, surface condition, also 'I'he qrade which a bicycle can be expected to ne-
<br /> affect the speed the cyclist wiil travel. Althouqh speed qotiate is dependent upon the length of the qrade, charac-
<br /> of over 30 mph is attainable, the averaqe cyclist travels teristics of the bicyclist (age, weiqht, condition, etc.),
<br /> ' at much lower speeds. characteristics of the bicycle (type of cycle, qear ratios,
<br /> weight, tires, etc.), wind velocity, air resistance and road
<br /> Speed bumps intended to caus�cycliats to slow down surface. As all of these determinants are variable, it is
<br /> in advance of intersections etc. shall not be used because not possible to specify definite desiqn qrades. Generally
<br /> ' they may cause a cyclist to fall and result in injuries. The spealdng, the amount of energy required to use a bicycle
<br /> desiqn speed is normally determined by the speed of the route will affect the usage of the route and, thus, qrades
<br /> hiqhway or street. These design speeds are qenerally ad- should be kept to a minimum.
<br /> ' equate for cyclist's use.
<br /> The grade for on-road bikeways is qenerally adequate
<br /> For off-road bikeways, the design speed should be for cyclists, with little or no room for desiqn chanqe since
<br /> 20 mph. For lonq downqrades, lonqer than 500 feet and it is a part of the road structure.
<br /> ' steeper than 4 percent, a desiqn speed of 30 mph should
<br /> be used at the downhill end. Desirably, a qrade of Sq should not be lonqer than
<br /> 100 feet and a qrade of 2% should not be longer than 500
<br /> B. CURVATURE feet. Grades of 59'o for over 300 feet and 2%for over 1,500
<br /> ' feet should be avoided. Grades should be minimized even
<br /> On-road bikeways will have curvature as dictated at the expense of havinq to provide added curvature or
<br /> by the highway. Since these curves are desiqned to accom- travel distance, within the practical limits for the site.
<br /> modate motor vehicles, they are qenerally adequate for The designer is offered some latitude in selectinq profile
<br /> , bicyclists. qrades for off-road bikeways but this is not the case for
<br /> on-road bikeways.
<br /> For off-road bikeways, the minimum radius of cur-
<br /> vature must be consistent with the desiqn speed of the
<br /> facility. The followinq desiqn values are applicable where
<br /> only standard cross-slope (.02 foot per foot) is provided:
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