A large grain elevator is located 40 ft from the centerline of a two- lane highway, which has 12-ft lanes. The elevator is situated on the inside of a l2° horizontal curve. a) Assuming that the elevator is the only sight restriction on the curve, what is the minimum sight distance along the curve? b) What should be the maximum speed recommended for this curve? c) If the designer wants to have the design speed of 10 mph higher that the recommended speed, what is the distance required for the movement of the elevator?

A curve of radius 250 ft and e  0.08 is located at a section of an existing rural highway, which restricts the safe speed at this section of the highway to 50% of the design speed. This drastic reduction of safe speed resulted in a high crash rate at this section. To reduce the crash rate, a new alignment is to be designed with a horizontal curve. Determine the minimum radius of this curve if the safe speed should be increased to the design speed of the highway. Assume fs= 0.17 for the existing curve, and the new curve is to be designed with e = 0.08

A horizontal curve is being designed to connect two tangents that intersect on a rural collector road with a specified design volume of 2500 veh/day (i.c. design speed 60 mph). It is expected that, because of right-of-way restriction, a large billboard will be placed at a distance of 50 ft from the centerline of the inside lane. If the terrain can be described as level and only a minimal amount of snow is expected on the road, determine the minimum radius of curve. Assume maximum superelevation rate (e) of 0.1 and fs=0.12. Ans: 1090 ft

A two-lane highway is being expanded to four lanes with the original highway consisting of the northbound lanes and the new highway carrying the southbound lanes. At one location, the southbound facility crosses over an existing pipeline. The resulting vertical curve needs to be at least 10 feet above the top of the pipeline. The initial grade is -4 and G2 is +2. The design speed for the new highway is 60 mi/hr. (1) Is the length of the design curve greater or less than the required stopping distance? (2) The PVI is at station 425+74 and the elevation is 980 ft. If the pipeline is at station 424+54 and the elevation of the top of the pipeline is 985 ft, is the distance from the curve to the top of pipeline adequate to meet the 10 feet required cover? I recommend drawing the cross-section of the curve including the location of the pipeline when answering this question. Note that instead of clearance from the curve up to the the bottom of the overpass (example in the book), this is…

As a roadway designer you are asked to design a horizontal curve for a two-lane road that are 12' wide each. There is an enormous boulder in the way of the construction zone and the minimum distance needed to excavate towards to the center must be solved for. The distance is required to sustain a speed of 55mph at a maximum super-elevation of 10%. Find the minimum distance from the boulder to the center of the road that fulfils the design requirement

A vertical curve was designed in 2006 for SSD requirements at a design speed of 120 km/h to connect grades G1 = +1% and G2 = -2%. The curve is to be redesigned for 120 km/h design speed in the year 2050. Vehicle braking technology has advanced such that vehicle deceleration rate has increased by 40% relative to 3.4m/s2 value used in the original design. However, due to the higher percentage of older people in the driving population, design reaction times have increased by 20%. Also, because vehicles have become smaller, the driver’s eye height is assumed to be 0.9 m above pavement. Compute the difference in design curve lengths for the 2006 and 2050 designs. Assume heye =1.08 and hobs = 0.60 m.

A horizontal curve is to be designed to connect two tangents on a rural principal arterial with a design speed of 110 km/h. The station of the BC is 545+13.65. It is expected that an existing building will be located at a distance of 15 m from the centerline of the inside lane. Determine the minimum radius that will satisfy the sight distance and superelevation requirements.

A section of a two-lane rural highway consists of a -3% grade intersecting a +4.5% grade. The speed limit on the highway is 55 mph. The height of headlights of an average car is 2.4 feet with a beam angle of 1.50. Determine the length of sag vertical curve that joins the two grades, considering a safe stopping maneuver