Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Question
Chapter 4, Problem 5P
To determine
The range of values that would be expected to contain the middle 95 percent of speeds
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Students have asked these similar questions
The city received a complaint of afternoon
traffic speeding in a residential area. The
city suspected this was related to students
leaving a nearby school. The first action
taken by the city was to quantify the facts
by conducting a spot speed study. The city
decided to use the stopwatch method
because of their limited resources. The
Speed
(mph)
21.4
22.2
23
24
Frequency of
Vehicles
3.
25
26.1
27.2
28.9
30
31.5
33.3
35.2
37.5
9.
11
13
posted speed limit is 30 mph. The study
was conducted on a Wednesday and started
at 3:00 p.m. The time was selected to
correspond to the period when most
students leave the school. The study
continued until a sample size of 100
9
10
10
9.
40
42.8
vehicles was measured.
A spot speed study was conducted on a freeway on which the mean speed and standard deviation were found to be 72.4 km/h and 5.4 km/h, respectively. What is the range of values that would be expected to contain the middle 95% speeds
1 what is top and the lowest range
Consider only a single lane of a highway. Based on extensive data from an urban freeway it is assumed thatfree-flow speeds (i.e., there are no jams) can best be represented by a Normal distribution with mean andstandard deviation 119 km/h and 13.1 km/h, respectively.1. What is the probability that the speed of a randomly selected vehicle is between 100 and 120 km/h?2. What is the expected number of vehicles between two vehicles that exceed the posted speed limit of100 Km/h?
You can use the Z table for calculating the final answer. You can also write your final answer in form ofR functions or as PDF/CDF of statistical distributions with correct arguments.
Chapter 4 Solutions
Traffic and Highway Engineering
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Similar questions
- A spot speed study was conducted on a freeway on which the mean speed and standard deviation were found to be 72.4 km/h and 5.4 km/h, respectively. What is the range of values that would be expected to contain the middle 95% speeds 1 what is top range 2. what is the lowest rangearrow_forwardA construction zone on a highway has a posted speed of 40 kmph. The speeds of vehicles passing through this construction zone are normally distrbuted with a mean of 45 kmph and a standard deviation of 4 kmph. a.) What is the probability that a vehicle passing through the construction zone exceeds the posted limit? b.) What is the probability that a vehicle passing through the construction zone is travelling at speeds between 38 and 49 kmph? c,) For the next 30,000 vehicles passing through the construction zone, how many will be passing through the zone with speed less then 50 kmph?arrow_forwardFor a spot speed study in which 100 observations were obtained, the mean speed was 52 km/h and the standard deviation was 4.6 km/h. (BO0K: Traffic % Highway engineering, N. Gruber SI unit) What is the margin of error on the estimate of true mean speed obtained from this sample? What is a reasonable estimate of the 85th percentile speed based on the information available?arrow_forward
- Question 3: (a) A section of highway is known to have a free-flow speed of 95 km/h and a capacity of 3300 veh/h. Your summer student indicates that the average time in between passing vehicles was 1.6 seconds during an hour of monitoring. If the linear speed-density relationship applies, what was the space-mean speed of the vehicles during the hour of monitoring?arrow_forwardSpot speed study has been carried out on a highway and collected data is shown in the table below. Speed range (kmph) No. of vehicles observed 0-10 10 10-20 13 20-30 15 30-40 12 40-50 16 Determine the design speed for checking the geometric design of the highway.arrow_forwardIt was determined through a survey that the rate of vehicles crossing a point on a highway is 400 veh/h. Calculate the probability of 5 vehicles arriving at an interval of 60 sec.arrow_forward
- Calculate the minimum passing sight distance required for a two-lane rural roadway that has a posted speed limit of 45 mi/h. The local traffic engineer conducted a speed study of the subject road and found the following: average speed of the passing vehicle was 47 mi/h with an average acceleration of 1.43 m/h/sec, and the average speed impeder vehicles was 40 mi/h. Write your step by step solutions.arrow_forward5. Calculate the minimum passing sight distance required for a two-lane rural roadway that has a posted speed limit of 45 mi/h. The local traffic engineer conducted a speed study of the subject road and found the following: average speed of the passing vehicle was 47 mi/h with an average acceleration of 1.43 mi/h/sec, and the average speed of impeder vehicles was 40 mi/h.arrow_forwardQ1 (a) i. 10,000 vehicle speed traffic data were collected during the weekday on route FT050 at Batu Pahat, Johor. Suggest how to quantify and describe the basic characteristic of this data. Then explain how the method you suggested can help others to understand the data. (4 marks) ii. Consider the following data from 11 truck speed data climbing a hilly road. Compute 5 (FIVE) basic statistics of the sample speed as following: Sample mean Median а. b. с. Variance d. Range Standard error of the mean е. Speed (km/h) 25 Truck 1 2 35 3 55 4 15 40 6. 25 7 55 8. 35 9. 45 10 11 20arrow_forward
- Measurements from a single-lane roadway reveal that the average spacing and headway between passing vehicles are 200 ft and 2.4 seconds, respectively. What is the flow [veh/hr], density [veh/mi] and average speed [mi/hr] of traffic on this roadway?arrow_forward6-5 The data shown below were obtained on a highway. Use regression analysis to fit these data to the Greenshields model and determine (a) the mean free speed, (b) the jam density, (c) the capacity, and (d) the speed at maximum flow. Speed (mi/h) Density (veh/mi) 14.2 85 24.1 70 30.3 55 40.1 41 50.6 20 55.0 15arrow_forwardCalculate the minimum passing sight distance required for a two-lane rural highway that has a posted limit of 72 kph. The local traffic engineer conducted a speed study of the subject road and found the following: Average speed of passing vehicle= 76 kph Average acceleration of passing vehicle= 2.3 kph/sec Average speed of impeder vehicles= 64 kph Show complete solution. Need ASAP. Thank you.arrow_forward
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