Speed data collected on an urban roadway yielded a standard deviation in speeds of 4.8 mi/h. (a) If an engineer wishes to estimate the average speed on the roadway at a 95% confidence level so that the estimate is within 2 mi/h of the true average, how many spot speeds should be collected? (b) If the estimate of the average must be within 1 mi/h, what should the sample size be?

Speed data collected on an urban roadway yielded a standard deviation in speeds of 4.8 mi/h. (a) If an engineer wishes to estimate the average speed on the roadway at a 95% confidence level so that the estimate is within 2 mi/h of the true average, how many spot speeds should be collected? (b) If the estimate of the average must be within 1 mi/h, what should the sample size be?

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

The data shown below were obtained by time-lapse photography on a highway. Use regression analysis to fit these data to the Greenshields model and determine the following. Speed (mi/h) Density (veh/mi) 84 16.2 24.7 69 33.3 54 39.7 40 52.0 19 55.1 14 (a) the mean free speed (in mi/h) mi/h (b) the jam density (in veh/mi) veh/mi (c) the capacity (in veh/h) veh/h (d) the speed at maximum flow (in mi/h) mi/h
For this question, you will be required to upload your approach and solution. Determine the AADT on a rural primary road for the following data: Time of day Volume 0600 - 0700 435 0700 - 0800 550 0800 - 0900 572 Data collected was on a Wednesday during the month of August.
Please solve this problem with neat step by step solutions
Note:hand written solution should be avoided.
The following travel times were observed for 4 vehicles traveling a one km segment of the SLEX. It is required to determine the space mean speed of these vehicles
QUESTION 9 The adjustment for the access point density is based on empirical studies indicating that for each access point per mile, the estimated FFS decreases by 0.25 mi/h, regardless of the type of median. Note that these access points are those that influence traffic flow and that access points that go unnoticed by drivers are not included in the calculation of the access point density. Therefore, what is the expected reduction (mph) in FFS when the access density is 4 access points per mile. (enter a positive value)
Highway 6.2
Question 35 24-h traffic count at a road section was observed to be 1000 vehicles on a Tuesday in the month of July. If daily adjustment factor for Tuesday is 1.121 and monthly adjustment factor for July is 0.913, the Annual Average Daily Traffic (in veh/day, round off to the nearest integer) is
A freeway traffic stream was observed to have a density of 22.0 veh/mi/ln when the mean speed was 55.0 mi/h. On another occasion at the same location, the jam density was found to be 132 veh/mi/ln. Assume Greenshields' model of traffic flow applies. The optimum speed (in mi/h) is: a) 22.0 b) 33.0 c) 55.0 d) 66.0 e) None of he above
engineer wishing to determine the travel time and average speed along a section of an urban highway as part annual trends analysis on traffic operations conducted a travel time study using the floating -car technique .He carried out 10 runs and obtained a standard deviation of +-3 mi/h in the speeds obtained .if 5% significance level is assumed is the number of test runs adequate?
4. The statistical data of an urban spot speed study is given below. A set of 130 observations of spot speeds made by timing vehicles through a "Trap" of 88ft. The stopwatch was used to obtain data. The stopwatch data are grouped into 0.2 sec. Classes. The first column of the table shows the midpoint of each group. The second column of the table shows the frequency of the observations. Compute the following statistical values. a) The speed of each time class in mph (show it in the third column) b) The cumulative percent of vehicles traveling at or below indicated speed shown in the third column in mph (show it in the forth column) c) Mean or average speed (time-mean speed), median, mode, standard deviation, standard error of the mean, average time, space-mean speed, variance, 15%, and 85% speed. d) Plot the cumulative percentage, and show the statistical values of item (c) on the graph. e) Plot the frequency distribution curve and show the statistical values on the graph.