Changes for second edition, 5 th printing of Fundamentals of Transportation Engineering May 2016

Transcription

1 Changes for second edition, 5 th printing of Fundamentals of Transportation Engineering May 2016 Most changes are minor, with the intent to improve wording or punctuation. The only significant changes in the text from the 4 th Printing are in Chapters 6, 10, and 11. These changes are marked by ** in the list of changes below. Renumbering sections, equations, etc. has been avoided wherever possible. Chapter 1 Transportation in Our Daily Lives Minor wording, punctuation, or spelling changes on pages 1.1, 1.6, 1.10, 1.11, 1.14, 1.15, and Sentence added to end of Leg 1 paragraph on page 1.15: Emerging technology regarding connected, automated, and autonomous vehicles is likely to shift that relationship. Definition of relinquishment added to Glossary on page Chapter 2 Traffic Flow: Theory and Analysis Minor changes in wording, punctuation, or figure format on pages 2.1, 2.12, 2.13, 2.16, 2.30, 2.48, 2.49 On page 2.12, In Indiana, for example, there are approximately permanent count stations, but about 11,000 miles of roadway on the state highway system. If the typical highway segment for traffic count purposes is two miles long, only about one in every segments has its own PCS. On page 2.18: Monitoring speeds on roadways Setting speed limits On page 2.20, after where N = minimum number of measured speeds, add If N<30 is calculated, a common practice is to use N=30. On page 2.22, after This means that only 19 vehicle speeds need to have been observed!, add However, standard practice is to collect a sample size of at least 30, if at all possible. On page 2.42, add to Equation 2.24: e = = base of the natural logarithm Just above Table 2.11, sentences are rewritten and added. They saw 15 vehicles in 2 minutes 15 seconds. When they repeated the process for the other direction on Steak Street, it took them 3 minutes to record 15 vehicles. The results of their data collection are shown in the "Direction One" and "Direction Two" columns of Table In the Direction One 15-sec patterns portion of Table 2.11, the number of vehicles seen in each 15-second interval is shown. On page 2.48, 18! should be 8! in the calculation for P(8). In Exercise 2.32 on page 2.65, Figures 2.22, 2.23, and 2.24 should be Figures 2.21, 2.22, and Chapter 3 Highway Design for Performance Font size changes on pages 3.21 and Chapter 4 Modeling Transportation Demand and Supply Punctuation changes on page Move the Balancing Ps and As paragraph at the start of Section to just after the Think About It box below Example 4.4. In Exercise 4.8B, a typical 3-person, 1-vehicle household. In Exercise 4.21A, vanpools carpools

2 Chapter 5 Planning and Evaluation for Decision-Making Under Equation 5.12: where L = number of alternatives less deserving than Segment B D = Total number of segments with factor values different from Segment B s. Page 5.27: There is a common tendency to make give the more most important factor a weight that is too high Chapter 6 Safety on the Highway Minor changes to wording and punctuation on pages 6.51, 6.52, and Page 6.4: R. Kumar (1985) K. Rumar (1985) **Section has been revised as follows: Consider a vehicle traveling up an incline. The forces resisting forward (uphill) motion in Figure 6.20 are R roll = W * f roll cos = the sum of the rolling resistance from the tires of a vehicle weighing W lbs. f roll is the coefficient of rolling resistance, approximated by f roll = 0.01*[1+(V/147)] when V is vehicle velocity in fps. = the angle between the grade and the horizontal. R aero is the aerodynamic force, which will be treated as negligible in this chapter. R grade = W sin = the component of gravity acting down the incline. FIGURE 6.20 Forces acting on an automobile traveling uphill There is also the resistance to acceleration caused by the vehicle s mass m, which is where W= weight of the vehicle, lbs g is the gravitational constant, 32.2 ft/sec 2 a = vehicle acceleration, ft/sec 2. R accel = ma = W a g The tractive force F t from the vehicle s engine acting through the wheels must overcome these resistive forces. According to Newton s second law of motion, an object accelerates when the net force acting on it is not zero. If the car is moving uphill at a constant speed, the tractive force equals the sum of the resisting forces. By substitution, Equation 6.15 becomes Equation 6.16: Ft Raccel Rroll Rgrade Raero (6.15)

3 W Ft a W*fr cos Wsin Raero (6.16) g The same relationships apply to braking, with the rolling resistance being replaced by the force operating to stop the car through the friction applied to the highway. The braking deceleration rate is usually assumed to be a constant, if the car does not go into a skid. If the coefficient of friction is f, the initial velocity is v 0, and the final velocity is v f, the distance D br traveled during the time the brake is applied is given in Equation D If braking takes place on a hill with grade G, the braking distance will be D br br 2 2 v0 vf (6.17) 2a v0 vf v0 vf 2g(f tan ) 2g(f G) where G is the grade in percent divided by 100 and f is the dimensionless coefficient of friction for the road. Chapter 7 Highway Design for Safety On page 7.7, change definition of c to c is a parameter related to the rate of change in grade, as derived below Also on page 7.7, At the origin x =0, the slope grade is G 1. and It is also the rate of change of the slope grade, On page 7.24, change the first two sentences in the second paragraph to Because the superelevation is a side slope (Figure 7.21), it has a practical limit. The side slope cannot be so great, that a standing car on snow or ice would slide down. In Exercise 7.3, Determine the length of the vertical curve; the initial slope grade G 1 and the elevation of the sag curve at its low point? Chapter 8 Intersection Design Add to the Think About It box on page Does the dilemma zone vary from driver to driver? The label of the vertical axis in Figure 8.3 should be Percent. Exercise 8.5. T he distances from curb to view obstruction, using the notation of Figure 8.5, are: a" = 40 feet, b" = 73 feet, c" = 94 feet, d" = 85 feet. and B. Submit a copy of Figure 8.6 with Chapter 9 Highway Design for Rideability (6.19) Exercise 9.5 should now read. Compute the annual ESAL on a flexible pavement for the truck traffic summarized in the table below, using the fourth power formula and assuming a 320-day year. (Using 320 days per year compensates for reduced traffic on weekends and holidays.) Load distribution, front/rear in the table pertains to the load from combination (not single unit) trucks that is in excess of the load on steering axle. Truck GVW (lbs) Average Weekday Traffic Data Average Weight Number of trucks 3-axle* single unit 5-axle 3-S2 5-axle 2-S1-2** 20,000 to 40,000 32K ,100 to 66,000 58K ,100 to 80,000 76K ,100 to 110, K Load on steering axle - 12,000 lbs 14,000 lbs

4 Load distribution, front/rear equal 60/40 equal * Single steering axle + tandem drive axle ** Single steering + single drive axle, single axle on semi-trailer, two single axles on full trailer. Chapter 10 Public Mass Transportation ** Revise the paragraph after the Think About It box on page as follows: If the elasticity is more negative than -1, the percent decrease in transit ridership is greater than the percent increase in fare, and the demand for transit is said to be elastic. If is less negative than -1, the demand is inelastic. Because transit agencies are concerned about how revenue changes after a fare change, apply shr = to the MBC case above. If MBC would raise its fare from $1.00 to $1.50 (50 percent), it would lose 1650 percent of its riders. Calculate the farebox (operating) revenue before and after the fare change: Before: $1.00* 10,000 = $10,000 After: $1.50 * 8350 = $12,525 Because ridership is expected to decrease only 0.33 percent for every one percent increase in fare, operating revenue would actually increase. In actual practice, different groups of riders react differently to fare changes. Example 10.4 will demonstrate. ** Replace Example 10.4 as follows: Example 10.4 Predicting transit revenue changes by fare category using demand elasticity. The monthly ridership and other information by fare category for a transit system is given in the table below. Fare category Pax/mo $/ride (shr) Base 286,700 $ Student 98,400 $ ADA ** 19,000 $ ** ADA refers to the special curb-to-curb demand responsive service provided to persons who qualify under the Americans with Disabilities Act. A. Which of the fare categories has the least elastic demand with respect to fare? Explain. B. What is the system s monthly fare revenue for each fare category at the current fare levels? C. Using the shrinkage ratio values given in the table, estimate the ridership and fare revenue for each category if the fares are raised to $1.50, $0.75, and $3.00, respectively. Solution to Example 10.4 A. The ADA category has the least elastic demand, because it has the least negative value (-0.15). This means that, for every one percent increase in fare, ADA ridership will decrease less than Base or Student ridership. B. Base Fare Rev = 286,700 pax * $1.00/pax = $286,700. Student Fare Rev = 98,400 pax * $0.50/pax = $49,200. ADA Fare Rev = 19,000 pax * $2.00/pax = $38,000. C. Sample calculation for Student P0 = $0.50 and P1 = $0.75 using (10.16): (Q1 Q 0)P 0 (Q1 98,400)*0.50 shr = Q1 98,400 = (P P )Q ( )*98, *0.25*98, ,400 20,172 = 78,228. Student Rev1 = 78,228 pax * $0.75/pax = $58,671. = -20,172; Q1 =

5 Spreadsheet calculations for ridership and revenue after the proposed fare changes, by category, are shown in the table below. Fare category P0 Q0 (shr) P1 Q1 Rev0 Rev1 Base $ , $ ,828 $286,700 $361,242 Student $ , $ ,228 $49,200 $58,671 ADA $ , $ ,575 $38,000 $52,725 Chapter 11 Air Transportation and Airports Minor changes in wording, punctuation, or figures on pages 11.12, 11.14, 11.29, 11.33, 11.37, 11.40, and Beginning on page 11.14, tables numbered should be Tables Change table numbers accordingly on page At the start of Section 11.3 on page 11.18, the first paragraph now reads (new words in italics): As explained in Chapter 3, whenever the arrival rate (demand) exceeds the service rate (capacity), delay is the result. Within the terminal, a passenger can encounter delay at several points -- most often at check-in, at security screening, or in the boarding area. Airport terminal design is aimed at avoiding bottlenecks that can occur on the landside (see Figure 11.4). This section of Chapter 11 focuses on airside capacity. Section 11.4 will address delays that may occur on the airside. Renumber old Sections , , and to , , and ** Move the rest of old Section to the start of Section 11.4 DELAY AT AIRPORTS. Figure 11.8 becomes Figure Figure numbers 11.7, 11.8, 11.12, 11.17, 11.20, are not used. On page 11.38: This means that, percent of the time, the winds at the airport would have an allowable crosswind component if the runway was oriented at true azimuth magnetic compass direction (Runway 11/29). The most frequent landing would be from the west-northwest on Runway 11. At the end of Section , add an FYI box: FYI The wind rose in Figure is a version that shows more clearly all possible combinations of wind direction and speed. Some wind roses summarize wind directions using 16 vectors. For month-by-month wind roses for many airports over a 30-year period, refer to NCRS (undated). After Table 11.15, add an FYI box and some text: FYI If a runway is not level, find the effective length of the runway by reducing the length of the runway by 10 ft for every ft of difference between the high and low points of the runway centerline. Although in some cases, aircraft will use the runway in the uphill direction, this adjustment takes care of the downhill worst case. If a situation calls for finding the minimum runway length needed, add to your initial

6 solution 10 ft for every ft of difference between the high and low points of the runway centerline. Example illustrates. Added reference: NCRS undated. National Water and Climate Center, National Water and Climate Center, United States Department of Agriculture, accessed 15 May Change Exercise 11.5C to: Find an airport with % on-time arrival performance < 80. What are its two most frequent causes? Chapter 12 Moving Freight Chapter 13 The Path to a Sustainable Transportation System Page major part to play in reducing emissions and the indecreasing use of non-renewable energy. New second sentence in Section : (Energy analysis of freight modes, including energy intensity, is covered in Section 12.7.) Remove Section Tires for Tractor Trailer Trucks, including Figure 13.9 and Table Remove Franzese reference on page Exercises 13.2, 13.3, and 13.4 become 13.3, 13.5, and 13.9, respectively. Exercise numbers 13.2, 13.4, 13.6, 13.8, and are saved for future use. New exercises are: 13.7 The impact of self-driving vehicles (SDVs). Advocates point out the following aspects of SDVs. a. There will be fewer crashes, because the human element (see Figure 6.3) has been eliminated. b. Available roadway space can be used more efficiently because SDVs can maintain smaller headways. c. There will be fewer parking spaces needed, because an SDV can drop off its occupant(s) and (i) seek other riders, (ii) go back to home base, or (iii) go to a special SDV parking facility. d. Persons who cannot drive now because of age or disability will have the same mobility options as others. e. Shared SDVs will replace some or all household-owned vehicles, thereby reducing the number of vehicles on the roadways. A. For each of the positive aspects listed above, point out some possible negative aspects that should be included in the analysis of SDVs. B. Are there any other features of SDVs that should be considered positive, negative, or both? State them concisely Urban Design Rating System. LEED-ND is system used to rate neighborhood design (ND) as part of the Leadership in Energy and Environmental Design (LEED) program created by the U.S. Green Building Council. Several of its many criteria involve transportation, in particular [Schwartz 2008, p ] A. Reduced parking footprint. No more than 20% of the total development footprint area for surface parking. B. Walkable streets. Continuous sidewalks or footpaths provided along both sides of all streets within the project. C. Street network. If cul-de-sacs are part of the project, include a pedestrian or bicycle through connection in at least 50% of the cul-de-sacs. D. Transit facilities. Provide covered and at least partially enclosed shelters, adequate to buffer wind and rain, with at least one bench at each transit stop within the project boundaries. Provide message boards devoted to providing basic schedule and route information at each transit stop that borders or falls within the project. For a neighborhood ( project ) assigned to you by your instructor, or for a neighborhood you choose as likely to have a sustainable neighborhood design, assess the project in terms of the four criteria given above. Provide maps and photographs, if required by your instructor.

7 13.12 Measuring transportation for sustainability. How does an engineer or planner know when a transportation system is contributing to a neighborhood s sustainability? What should be measured? Here are some proposed metrics [Litman 2016]: Personal mobility. Trips and vehicle-miles by each mode (nonmotorized, automobile, and public transport) Average commute time to/from workplace Per capita traffic crash and fatality rates. Affordability (percent of household budget devoted to transport) Per capita energy consumption, by fuel and mode Air pollution emissions (various types), by mode. For each of the measures listed, A. Comment on where it fits into the triple bottom line dimensions of performance introduced in Section , and explain why. B. Explain whether it is a good basis for deciding whether the design of a particular transportation system or component supports sustainability.