Approved Corrections and Changes for the Highway Capacity Manual 2000

Approved Corrections and Changes for the Highway Capacity Manual 2000 Updated 7/8/2005 Previous update 2/27/2004 TRB Committee AHB40, Highway Capacity and Quality of Service Unless stated otherwise, corrections apply to both the U.S. Customary and Metric versions. NEW PAGE ITEM CORRECTION APPROVAL DATE Chapter 6 Update variable symbol and definition according to changes made in Equation 20-16. 7-3 Last sentence on Change the last sentence to read The space mean speed is 1/13/2003 page 38.3 mi/h, calculated as (60)[3 (2.0 + 1.5 + 1.2)]. 7-6 4 th paragraph Change first sentence to read "The slope of any ray line drawn from the origin of the speed-flow curve represents the inverse of density, based " 8-2 Pedestrian Change the third sentence to read An average walking speed 1/13/2003 Characteristics of 4.0-ft/s is appropriate. 8-12 Ehibit 8-12 Change Facility descriptions for Detroit, MI to be I-96 1/13/2003 Jeffries Freeway at Warren and Lodge at W. Grand Blvd. 10-10 Ehibit 10-7 Correct service volumes (see attached tables). 10-11 Ehibit 10-8 Delete middle yellow interval and associated dotted line to 7/26/2003 reflect a standard green-yellow-red phasing sequence (see attached revised ehibit) 10-24 Correct chapter Change the third sentence following Ehibit 10-19 to read: reference Chapter 16 provides 10-36 Reference 6 Add at the end, 1982, specifically citing Mekky, A., On Estimating Turning Flows at Road Junctions, Traffic Engineering and Control Journal, Vol. 20:10, October 1979, pp. 486-487. 1/13/2003 10-45, 10-46 Equations A10-1 and A10-3, Ehibit A10-9 12-15 Replace Ehibit 12 7b Correct equations A10-1 and A10-3 and associated tet and Ehibit A10-9 for the Quick Estimation Method for Signalized Intersections in Appendi A (see attached material) Replace with Figure 7, NCHRP Project 20-7 (160). (See attached material.) 13-18 1 st paragraph Revise first sentence to read "Procedures in Chapter 24 generally apply to weaving segments between 500 to 2,500 ft long." For the metric version, " segments between 150 to 750 m long." 1/13/2003 15-2 Ehibit 15-1 Revise first item in Input bo to read Define segments 15-8 Equation 15-6 Replace with Equations 15-6a and 15-6b and redefine terms (see attached material). For the U.S. Customary version of the manual, substitute English units for the metric units shown. 15-16 Eample Prob. 1 In the table under Step 1, column two, change PF = 0.0 to PF = 1.0. 15-19 Eample Prob. 2, Revise worksheet numbers, metric version (see revised Worksheet material) Page 1 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION 15-20 Correct appendi Change the fourth checked sentence under The Facts to read: reference Segment lengths described in Appendi B, 15-22, Eample Prob. 4, Revise value in Step 4 for k = 0.4. Revise calculated values 15-23 solution steps and based on this change in other steps and worksheet on net 15-24, 15-25 worksheet Eample Prob. 5, solution steps page (see revised material). Revise formula in Step 3 for d. Revise value in Step 4 for k = 0.4. Revise subsequent values in other steps based on these changes (see revised material). 15-25 Appendi A Revise step 3 under LOS analysis to be: APPROVAL DATE 15-25, 15-26 Appendi A 3. Convert the hourly directional volumes to throughmovement 15-min flow rates by subtracting the turn movement volumes served by eclusive turn-lane lane groups and then divide this difference by the PHF. Revise the second set of seven steps under the planning analysis procedures (see revised material) 15-27 Appendi B Redefine steps 2, 4, and 5: 16-19, 16-152 Equation 16-10, Equation G16-8 2. Determine the appropriate FFS for each street segment. 4. Make test-car travel time runs over each street segment during the 5. Total travel speed for the entire urban street section should also Apply the following constraints for the delay and queuing progression factor formulas: (i) PF 1.0 and PF 2 1.0 for Arrival Types 1 and 2 (ii) PF 1.0 and PF 2 1.0 for Arrival Types 4 to 6 (iii) P 0.95 (R p 0.95/u) for both PF and PF 2 (iv) R p 0.95/y L for both PF and PF 2 (v) PF 2 = 1.0 for y L u (X L 1.0) (vi) R p (1 0.95*(1 u)/y L )/u for both PF and PF 2, and (vii) R p = 1.0 (P = u), therefore, PF = 1.0 and PF 2 = 1.0 for y L 0.95 (viii) If conditions (iii), (iv) and (vi) create inconsistent constraints on R p and P, set R p = 1.0 and P = u, therefore, PF = 1.0 and PF 2 = 1.0 May 2001 16-39 Bo 19 Change v/c to v/s Feb. 2004 16-47 Capacity Add flow ratios to WB direction = 0.313 Feb. 2004 worksheet And to NB direction = 0.289 16-50 Bo 24 Change v/c to v/s Feb. 2004 16-61 Eample Prob. 2, Supplemental Worksheet for Ped/Bike Effects on Permitted Left and Right Turns The EB left effective pedestrian green time should be 23.4 seconds. The subsequent calculations for the EB left will change slightly, with no change in the final ped-bike left turn adjustment factor. The WB right is already shown as 23.4 seconds, thus no change is required. 7/28/2001 Page 2 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION 16-73 Capacity Add flow ratios: worksheet NB pro = 0.084 NB per =0.000 SB per = 0.418 SB ThRt = 0.322 EB per = 0.237 EB ThRt = 0.170 16-144 Correct Equation F16-3 (both versions) WB ThRt = 0.233. The last part of Equation F16-3 should read: ct...u = 1 [ 1 min(1, X )] Q b APPROVAL DATE 16-151, Equations G16-2 Replace N LG in the denominator of each equation with 1/14/2002 16-152 through G16-5 (f LU *N LG ) 16-153 Equation G16-9 All places where (X L 1) appears should be replaced with 1/14/2002 (X L 1) + Q bl /(c L *T). All places where k B X L appears should be replaced with k B X. The results should be epressed in its simplest form. 16-153 Terms under Define k B as "second-term incremental factor" 1/14/2002 Equation G16-9 17-7 1 st paragraph and sidebar Change the third sentence in top paragraph to read "Base values of t c and t f are shown for two- and four-lane major streets. Due to limitations in the available data, this procedure is not applicable to intersections with si-lane major streets." 7/28/2001, 17-15 Equations 17-18, 17-19 and surrounding tet Delete the sidebar - "Base values for a si-lane major street are assumed to be the same as those for a four-lane major street." and replace with "This procedure is not applicable to intersections with si-lane major streets." The time to discharge the vehicles that arrive during the red is given by Equation 17-18. g q1 = vc(1 P) s where v is either v T or v L,prot. (17-18) The time to discharge the vehicles that arrive on the green and join the back of the queue is given by equation 17-19. g q2 = vcpg q1 s g eff v C P (17-19) where v is either v T or v L,prot. Page 3 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION APPROVAL DATE 17-16 Ehibit 17-12 Replace with two figures (see attached figures). 17-16 Redefining f f = the proportion of through and protected left turn traffic which departs the upstream signalized intersection and subsequently arrives at the subject two-way stopcontrolled intersection with respect to the through and protected left turn traffic departing the upstream signalized intersection. If there are no opportunities for vehicles to leave the roadway between the upstream signalized intersection and the TWSC intersection, then f is equal to 1. 17-16 Add Equation 17-21b and tet The downstream flow after a period equal to the green time after the platoon reaches the unsignalized intersection is v c,g and is given by: g g v q c,g = vr pf + (vc,ma vr pf )(1 F) Again, v is either v T or v L,prot 17-17 Equation 17-22 Replace with the multi-part equation and following tet (see attached material). 17-19 Equation 17-28 The equation 17-28 should read vc, 1.5vc,min (1 p ) if vc, > 1.5vc,min (1 p ) vc, u, = p 0 otherwise Remove the definition s under equation 17-28 and add, modified 7/26/2003 v c,min = as defined on page 17-17 Page 4 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION 17-19 New Equation Below equation 17-28 and the references to the 17-28a variables in the equation, insert the following: APPROVAL DATE 7/26/2003 The user can provide values of the proportion of unblocked time for a particular unsignalized intersection movement caused by upstream signals, the p values. Similarly the flow in the blocked period can also be given as v block in veh/h. The appropriate conflicting flow for the unblocked period is given by Equation 17-28a. v c, u, v = 0 c, v block p (1 p ) if v c, > v block otherwise (1 p ) 17-21 Flared Minor- Street Approaches 17-36 4 th paragraph, 2 nd sentence 17-53, 17-61, 17-62, 17-71, App. A Correct Worksheet 5a and 5b 18-24 Correct Eample Problem 3, Step 4 18-25 Correct Eample Problem 3, Step 5 (see attached material) Modify procedure (see attached material) The volume on the subject approach is increased incrementally until the degree of utilization on any one approach eceeds 1.0. Correct Worksheet 5a and 5b by changing the left column heading under Movement 2 and Movement 5 to V T instead of V T,prog. The top equation in step 4 should read: v tot = 48 + 27 + 40 + 21 + 20 = 156 p/cycle The last equation in step 5 should read: 46.0 14 t = 3.2 + + 2.7 * = 17.1s 4.0 16.0 20-1 Revise tet Paragraph to be added after the first paragraph under the section titled - Limitations of the Methodology " The operational analysis methodologies in this chapter are not intended to address capacity and traffic flow on two-lane highways in developed areas. Typically, two-lane highway segments in these areas (for eample, a two-lane highway through a small town) are subject to lower speed limits and have few to no passing zones. In addition, the effects of operations at signalized and/or unsignalized intersections, which may be significant, are not accounted for in the current methodology." Page 5 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION 20-3 Correct sentence Change the second sentence, sentence paragraph, under LEVELS OF SERVICE to read: Ehibit 20-2 reflects the boundary maimum values of percent 20-10 Equation 20-7 To reduce the potential for misunderstanding, HCM Equation (20 7) should be rewritten using the ep function, as shown below, rather than as e raised to a power: BPTSF = 100 (1 ep ( 0.000879v p )) 20-20 Replace Equation Replace with Equation 7, NCHRP Project 20-7 (160). (See 20 16 attached material.) 20-22 Equation 20-17 To reduce the potential for misunderstanding, HCM Equation (20 17) should be rewritten using the ep function, as shown below, rather than as e raised to a power: BPTSF d = 100 (1 ep (av b d )) 20-23 Replace Ehibit Replace with Table 10, NCHRP Project 20-7 (160). (See 20 20 attached material.) 20-24 Replace Ehibit Replace with Table 9, NCHRP Project 20-7 (160). (See 20 21 attached material.) 20-39 to Update Eample According to changes in Ehibit 20-20 and 20-21, and 20-41 Problem 3 Equation 20-16. 20-41 Correct ehibit In the fourth bo under Average Travel Speed, change the references references to (Ehibit 20-7 or 20-13) 20-42 Correct equation Change the coefficient to 2 as the multiplier for 1.7 in the in Step 2 denominator (numerator not shown) of the ATS pl calculation as follows: 1 2(1.7) 1+ 2.3 + + 1.11 1+ 1.11 20-42 to Update Eample According to changes in Ehibit 20-20 and 20-21, and 20-43 Problem 4 Equation 20-16. 22-19, Correct bo In the heagonal bo titled Adjust HCM capacities? delete 22-46 numbering the number 5 reference to a step. 22-56 Correct term in Revise the last term in the equation to read: equation A22-3 OFRD (i 1,p) 23-5 Ehibit 23-3 Correct Ehibit 23-3 figure to comply with Ehibit 23-2 values [no curves going beyond ma flow rate of 2400 pc/h/ln nor dropping below 50mph; LOS A density line angled to the left to intersect the 55mph curve at 600 pc/h/ln] (see revised figure) 24-8 Ehibit 24-7 Correct the N w equation for Type C configuration: the middle term should be 0.00011L and not 0.00011. 25-3 2 nd paragraph Revise first bullet to read "Maimum total flow approaching a merge or diverge area on the freeway (v F )" 25-6 Ehibit 25-5 Correct Equation 2 under 6-lane freeways: the third term should be 0.003296S FR and not 0.003296. 25-17 Equation 25-12 Change the units in the definition for v F to (pc/h) from (pc/h/ln) APPROVAL DATE 7/24/2004 Page 6 of 7

Updated 7/8/2005 Previous update 2/27/2004 NEW PAGE ITEM CORRECTION 27-10 Top paragraph Revise last sentence of top paragraph to read, For certain special conditions, users should multiply the base values by 1.2 (12) for heavy two-way flow (25-50% of passengers moving in the opposite direction) through a single door channel, and by 0.9 (16) for a low-floor bus. For primarily single-direction flow through either double-stream doors or two single-stream doors, the ehibit reduces the base values for a single door channel by a factor of 0.6 (14,15). 27-38 Correct chapter In the first checked sentence under Comments change the reference last reference to (from Chapter 16); 30-6 to Equations 30-5, Correct equations and ehibit under section titled 30-8 30-6, 30-7, 30-8, Determining Link Speed (see attached material) Ehibit 30-4 30-35 Correct Equation A30-15 (both versions) Correct Equation A30-15 by adding brackets as shown: 2 3600 X 2 8 X D = 5 + + 900T ( X 1) + ( 1) + v Tv 31-31 Add a reference Add an additional reference after number 1: 1a. Elefteriadou, L., G. List, J. Leonard, H. Lieu, M. Thomas, R. Giguere, R. Brewish, G. Johnson. Beyond the Highway Capacity Manual: A Framework for Selecting Simulation Models in Traffic Operational Analyses. In Transportation Research Record 1678, TRB, National Research Council, Washington, D.C., 1999, pp. 96 106. APPROVAL DATE 1/13/2003 Page 7 of 7

Highway Capacity Manual 2000 RECOMMENDED CHANGES FOR ERRATA (US CUSTOMARY) This table contains approimate values. It is meant for illustrative purposes only. The values are highly dependent on the assumptions used. It should not be used for operational analyses or final design. This table was derived using assumed values listed in the footnote. EXHIBIT 10-7. EXAMPLE SERVICE VOLUMES FOR URBAN STREETS (SEE FOOTNOTES FOR ASSUMED VALUES) Service Volumes (veh/h) Lanes A B C D E Class I 1 N/ A 850 920 1010 1130 2 N/ A 1710 1850 2020 2280 3 N/ A 2570 2770 3050 3420 4 N/ A 3440 3700 4060 4560 Class II 1 N/ A N/ A 670 840 880 2 N/ A N/ A 1470 1690 1770 3 N/ A N/ A 2280 2540 2660 4 N/ A N/ A 3090 3390 3550 Class III 1 N/ A N/ A 480 780 840 2 N/ A N/ A 1020 1600 1680 3 N/ A N/ A 1560 2410 2530 4 N/ A N/ A 2130 3220 3380 Class IV 1 N/A N/A N/A 780 800 2 N/ A N/ A N/ A 1570 1620 3 N/ A N/ A N/ A 2370 2430 4 N/ A N/ A N/ A 3160 3250 Notes N/A - not achievable given assumptions below. This table was derived from the conditions listed in the following table. Class I II III IV Signal density (sig/mi) 0.8 3 5 10 Free-flow speed (mi/h) 50 40 35 30 Cycle length (s) 110 90 80 70 Effective green ratio 0.45 0.45 0.45 0.45 Adj. sat. flow rate 1850 1800 1750 1700 Arrival type 3 4 4 5 Unit etension (s) 3 3 3 3 Initial queue 0 0 0 0 Other delay 0 0 0 0 Peak-hour factor 0.92 0.92 0.92 0.92 % lefts, % rights 10 10 10 10 Left-turn bay Yes Yes Yes Yes Lane utilization factor According to Ehibit 10-23, Default Lane Utilization Factors Chapter 10 - Urban Street Concepts 10-10 Signalized Intersections

Highway Capacity Manual 2000 RECOMMENDED CHANGES FOR ERRATA (METRIC) This table contains approimate values. It is meant for illustrative purposes only. The values are highly dependent on the assumptions used. It should not be used for operational analyses or final design. This table was derived using assumed values listed in the footnote. EXHIBIT 10-7. EXAMPLE SERVICE VOLUMES FOR URBAN STREETS (SEE FOOTNOTES FOR ASSUMED VALUES) Service Volumes (veh/h) Lanes A B C D E Class I 1 N/ A 830 940 1030 1130 2 N/ A 1690 1900 2060 2270 3 N/ A 2550 2850 3110 3400 4 N/ A 3410 3800 4150 4530 Class II 1 N/ A N/ A 710 840 870 2 N/ A N/ A 1540 1690 1750 3 N/ A N/ A 2370 2540 2630 4 N/ A N/ A 3210 3390 3510 Class III 1 N/ A N/ A 570 800 830 2 N/ A N/ A 1230 1610 1680 3 N/ A N/ A 1930 2430 2520 4 N/ A N/ A 2650 3240 3360 Class IV 1 N/A N/A N/A 660 780 2 N/ A N/ A N/ A 1460 1570 3 N/ A N/ A N/ A 2260 2370 4 N/ A N/ A N/ A 3050 3170 Notes N/A - not achievable given assumptions below. This table was derived from the conditions listed in the following table. Class I II III IV Signal density (sig/km) 0.5 2 3 6 Free-flow speed (km/h) 80 65 55 45 Cycle length (s) 110 90 80 70 Effective green ratio 0.45 0.45 0.45 0.45 Adj. sat. flow rate 1850 1800 1750 1700 Arrival type 3 4 4 5 Unit etension (s) 3 3 3 3 Initial queue 0 0 0 0 Other delay 0 0 0 0 Peak-hour factor 0.92 0.92 0.92 0.92 % lefts, % rights 10 10 10 10 Left-turn bay Yes Yes Yes Yes Lane utilization factor According to Ehibit 10-23, Default Lane Utilization Factors Chapter 10 - Urban Street Concepts 10-10 Signalized Intersections

Replace Ehibit 12-7b with the following figure: 100 90 80 Opposing Flow = 1600 pc/h Percent Time-Spent-Following 70 60 50 40 30 Opposing Flow = 200 pc/h 20 10 0 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 Directional Flow Rate (pc/h) 7/7/2005

Replace Ehibit 20-12 with the following: Ehibit 20-12. Adjustment (f np ) To Percent Time-Spent Following for Percentage of No- Passing Zones in Directional Segments Two-way Increase in percent time-spent-following (%) flow rate, No-passing zones (%) v p (pc/h) 0 20 40 60 80 100 Directional split = 50/50 200 9.0 29.2 43.4 49.4 51.0 52.6 400 16.2 41.0 54.2 61.6 63.8 65.8 600 15.8 38.2 47.8 53.2 55.2 56.8 800 15.8 33.8 40.4 44.0 44.8 46.6 1400 12.8 20.0 23.8 26.2 27.4 28.6 2000 10.0 13.6 15.8 17.4 18.2 18.8 2600 5.5 7.7 8.7 9.5 10.1 10.3 3200 3.3 4.7 5.1 5.5 5.7 6.1 Directional split = 60/40 200 11.0 30.6 41.0 51.2 52.3 53.5 400 14.6 36.1 44.8 53.4 55.0 56.3 600 14.8 36.9 44.0 51.1 52.8 54.6 800 13.6 28.2 33.4 38.6 39.9 41.3 1400 11.8 18.9 22.1 25.4 26.4 27.3 2000 9.1 13.5 15.6 16.0 16.8 17.3 2600 5.9 7.7 8.6 9.6 10.0 10.2 Directional split = 70/30 200 9.9 28.1 38.0 47.8 48.5 49.0 400 10.6 30.3 38.6 46.7 47.7 48.8 600 10.9 30.9 37.5 43.9 45.4 47.0 800 10.3 23.6 28.4 33.3 34.5 35.5 1400 8.0 14.6 17.7 20.8 21.6 22.3 2000 7.3 9.7 15.7 13.3 14.0 14.5 Directional split = 80/20 200 8.9 27.1 37.1 47.0 47.4 47.9 400 6.6 26.1 34.5 42.7 43.5 44.1 600 4.0 24.5 31.3 38.1 39.1 40.0 800 4.8 18.5 23.5 28.4 29.1 29.8 1400 3.5 10.3 13.3 16.3 16.9 32.2 2000 3.5 7.0 8.5 10.1 10.4 10.7 Directional split = 90/10 200 4.6 24.1 33.6 43.1 43.4 43.6 400 0.0 20.2 28.3 36.3 36.7 37.0 600-3.1 16.8 23.5 30.1 30.6 31.1 800-2.8 10.5 15.2 19.9 20.3 20.8 1400-1.2 5.5 8.3 11.0 11.5 11.9 7/7/2005

Replace Ehibit 20-21 with the following: Ehibit 20-21. Values of Coefficients Used in Estimating Percent Time-Spent Following for Directional Segments. Opposing demand flow rate, v o (pc/h) a b 200 0.0014 0.973 400 0.0022 0.923 600 0.0033 0.870 800 0.0045 0.833 1000 0.0049 0.829 1200 0.0054 0.825 1400 0.0058 0.821 1600 0.0062 0.817 Replace Equation 20-16 with the following: where: PTSF d = BPTSF d + f np Vd Vd + V 0 PTSF d = percent time-spent-following in the direction analyzed, BPTSF d = base percent time-spent-following in the direction analyzed, f np = adjustment for percent no-passing zones in the direction analyzed V d = directional passenger-car equivalent flow rate (pc/h) V 0 = opposing direction passenger-car equivalent flow rate (pc/h) 7/7/2005

Highway Capacity Manual 2000 f N = adjustment for number of lanes from Ehibit 23-6 (mi/h); and f ID = adjustment for interchange density from Ehibit 23-7 (mi/h). Average Passenger-Car Speed (mi/h) 80 70 60 50 40 30 20 10 EXHIBIT 23-3. SPEED-FLOW CURVES AND LOS FOR BASIC FREEWAY SEGMENTS Free-Flow Speed, FFS = 75 mi/h 70 mi/h 1300 65 mi/h 1450 60 mi/h 1600 55 mi/h 1750 LOS A B C D E Density = 11 pc/mi/ln 18 pc/mi/ln 26 pc/mi/ln 35 pc/mi/ln 45 pc/mi/ln 0 0 400 800 1200 1600 2000 2400 Flow Rate (pc/h/ln) Note: Capacity varies by free-flow speed. Capacity is 2400, 2350, 2300, and 2250 pc/h/ln at free-flow speeds of 70 and greater, 65, 60, and 55 mi/h, respectively. For 70 < FFS 75 (3400 30FFS) < v p 2400 S = FFS FFS 160 2.6 v p + 30FFS 3400 3 30FFS 1000 For 55 FFS 70 and for flow rate (v p ) (3400 30FFS) < v p (1700 + 10FFS), For S = FFS 1 2.6 v ( 7FFS 340) p + 30FFS 3400 9 40FFS 1700 55 FFS 75 and v p (3400 30FFS), S = FFS BFFS Estimation of FFS for an eisting or future freeway segment is accomplished by adjusting a base free-flow speed downward to reflect the influence of four factors: lane width, lateral clearance, number of lanes, and interchange density. Thus, the analyst is required to select an appropriate BFFS as a starting point. Adjustment for Lane Width The base condition for lane width is 12 ft or greater. When the average lane width across all lanes is less than 12 ft, the base free-flow speed (e.g., 75 mi/h) is reduced. Adjustments to reflect the effect of narrower average lane width are given in Ehibit 23-4. 23-5 Chapter 23 - Basic Freeway Segments Methodology

Highway Capacity Manual 2000 where c = capacity (veh/h), PHF = peak-hour factor, and g/c = effective green time per cycle. Refer to Equation 16-4 for definitions of all other factors. See Chapter 16, Signalized Intersections, for the adjustment factor values. See Chapter 10, Urban Street Concepts, for default values and approimation procedures for adjustment factors. For arterials with all-way stops controlling the link capacity, procedures in Chapter 17, Unsignalized Intersections, should be used to estimate the through movement capacity at each intersection. Capacity Tables The accuracy of the speed estimates are highly dependent on the accuracy of the estimated capacity for the facility. Consequently, it is recommended that each analyst use capacities that are specific to each link whenever possible. However, it is recognized that this procedure is not always feasible. The analyst may select sets of default values for the various capacity adjustment factors that vary by functional class (freeway, highway, arterial, collector, local), area type (downtown, urban, suburban, rural), terrain type (level, rolling, mountainous), and other conditions. These default values may be substituted into the above capacity equations to develop tables of link capacity values that vary by functional class, area type, general terrain, and number of lanes. Traversal time plus node delay equals segment travel time Determining Link Speed The vehicle speed for the link is computed using Equation 30-4. where L S = R + D 3600 S = link speed (mi/h), L = link length (mi), R = link traversal time (h), and D = node delay for link (s). (30-4) See Appendi A for methods to estimate node delay Node delay is computed only for signal- or stop-sign-controlled intersections at the end of the link. All other intersection-related delays that occur in the middle of the link are incorporated into the link traversal time calculation. The node delay estimation procedure is described in Appendi A. The calculation requires information on all of the intersection approaches at the node in order to compute the delay on each link feeding the intersection. If the available travel demand model software package is unable to compute node delay, it can be approimated by using the node approach capacity rather than the link capacity in the computation of traversal time. In this situation the node delay is set to zero in Equation 30-4. The link traversal time, R, is computed using Equation 30-5. where R = R o + D o + 0.25T (X 1) + (X 1) 2 16J * X * L2 + T 2 R = link traversal time (h), R o = link traversal time at link FFS (h), D o = zero-flow control delay at signalized intersection (h), (30-5) Chapter 30 - Areawide Analysis 30-6 Methodology

Revisions [new equation] (30-5) 2 ( X 1) 2 16J X * L R = Ro + Do + DM + 0.25NT ( X 1) + + 2 2 N T where: [add the following] D M N = segment delay between signals (equals zero if no signals)(h) = number of Signals (equals one if no signals)

Highway Capacity Manual 2000 T = epected duration of demand (typically 1 h) (h), X = link demand to capacity ratio, J = calibration parameter, and L = link length (mi). The link traversal time for free-flow conditions (R o ) is computed from the FFS, using Equation 30-6. R o = L (30-6) S o where R o = FFS link traversal time (h), L = link length (mi), and S o = link FFS (mi/h). The zero-flow control delay for signalized intersections (if any) on the link is computed using Equation 30-7. D o = N 3600 *DF *C 2 1 g 2 C (30-7) where D o = zero-flow control delay at signal (h), N = number of signals on link, 3600 = conversion from seconds to hours, g/c = average effective green time per cycle for signals on link (see Ehibit 10-12 for default values) (s), C = average cycle length for all signals on link (see Ehibit 10-12 for default values) (s), and DF = adjustment factor to compute zero-flow control delay (0.9 for uncoordinated traffic-actuated signals, 1.0 for uncoordinated fied-time signals, 1.2 for coordinated signals with unfavorable progression, 0.90 for coordinated signals with favorable progression, and 0.60 for coordinated signals with highly favorable progression). The calibration parameter J is selected so that the traversal time equation will predict the mean speed of traffic when demand is equal to capacity. Substituting = 1.00 in the traversal time equation and solving for J yields Equation 30-8: Calibration parameter J is used to arrive at a predicted mean speed when demand equals capacity where J = (R c R o )2 L 2 (30-8) J = calibration parameter, R c = link traversal time when demand equals capacity (h), R o = FFS link traversal time (h), and L = link length (mi). Ehibit 30-4 shows values for J that were selected to reproduce the traversal times at capacity predicted by the analysis procedures in Part III of this manual. Some older software may not be able to implement Equation 30-8, so the formula and recommended parameters for the more traditional BPR curve are provided in Appendi C as an alternative method for estimating link traversal times. See Appendi C for alternative approach using BPR curve 30-7 Chapter 30 - Areawide Analysis Methodology

(30-6) Note that the free flow speed (S O ) for signalized streets is defined as the mid-block free flow speed between signals. For this reason a zero flow control delay (D O ) and a segment delay (D M ) are added to the link travel time at zero flow. (30-7) Insert 1: The segment delay between signals (D M ) is computed by subtracting the Segment Running Time per mile (T R ) (obtained from Ehibit 15-3) from the free flow travel time per mile for the signalized urban street and multiplying the result by the total length of the street. D M equals zero if there are no signals on the street or if they are so far apart that they do not affect the speed of traffic between signals. The segment delay (D M ) is computed according to Equation 30-7a. DM = L ( TR To ) 3600 (30-7a) where: [add the following] D M = segment delay (h) L = link length (mi) T R = running time per mile (sec) T O = running time per mile at free flow speed (sec) The running time per mile (T R ) is obtained from Ehibit 15-3 according to the urban street class, free flow speed, and the average distance between signals on the link. The running time per mile at free flow speed (T O ) is computed according to Equation 30-7b. T o = L S o (30-7b) where: L = Link length (mi) T O = running time per mile at free flow speed (sec) S O = free flow speed (mi/h) J = ( R R D D ) c o L o 2 M 2 (30-8) where: [add the following] D 0 = zero flow control Delay (h) D M = segment delay between signals (h)

Highway Capacity Manual 2000 EXHIBIT 30-4. RECOMMENDED PARAMETERS FOR TRAVERSAL TIME J Facility Type Signals per mi Free-Flow Speed (mi/h) Speed at Capacity (mi/h) J (h 2 /mi 2 ) Freeway N/A 75 54 2.69 10-5 Freeway N/A 70 53 2.10 10-5 Freeway N/A 65 52 1.48 10-5 Freeway N/A 60 51 8.65 10-6 Freeway N/A 55 50 3.31 10-6 Multilane Highway N/A 60 55 2.30 10-6 Multilane Highway N/A 55 51 2.03 10-6 Multilane Highway N/A 50 47 1.63 10-6 Multilane Highway N/A 45 42 2.52 10-6 Two-Lane Highway N/A 69 44 6.91 10-5 Two-Lane Highway N/A 63 38 1.14 10-4 Two-Lane Highway N/A 56 31 2.02 10-4 Two-Lane Highway N/A 50 25 4.00 10-4 Two-Lane Highway N/A 44 19 9.29 10-4 Arterial Class I 0.2 50 33 5.67 10-5 Arterial Class I 0.6 50 19 4.68 10-4 Arterial Class I 1.6 50 10 3.32 10-3 Arterial Class II 0.3 40 25 1.28 10-4 Arterial Class II 0.6 40 18 5.02 10-4 Arterial Class II 1.3 40 11 2.03 10-3 Arterial Class III 1.3 35 11 2.24 10-3 Arterial Class III 1.9 35 8 4.55 10-3 Arterial Class III 2.5 35 6 8.13 10-3 Arterial Class IV 2.5 30 6 8.12 10-3 Arterial Class IV 3.1 30 5 1.37 10-2 Arterial Class IV 3.8 30 4 1.82 10-2 Note: N/A = not applicable. Determining Performance Measures Computation of performance measures for intensity, duration, etent, variability, and accessibility is described. Intensity The possible performance measures for measuring the intensity of congestion on one of the highway subsystems (freeway, rural highway, and arterial) are computed from one or more of the following: person-hours of travel, person-hours of delay, mean trip speed, and mean trip delay. If average vehicle occupancy (AVO) data are not available, the performance measures are computed in terms of vehicle-hours rather than person-hours. Equation 30-9 is used to compute person-hours of travel. where PHT = total person-hours of travel, v i = vehicle demand on Link i, AVO i = average vehicle occupancy on Link i, L i = length of Link i (mi), and S i = mean speed of Link i (mi/h). PHT = AVO i *v i * L i S i (30-9) Chapter 30 - Areawide Analysis 30-8 Methodology

Revised information for: EXHIBIT 30-4. RECOMMENDED PARAMETERS FOR TRAVERSAL TIME J Facility type Signals per mi Free-Flow Speed Speed at Capacity J (h 2 /mi 2 ) Freeway 53 2.95 10-5 Freeway Freeway Freeway Freeway Multilane Highway Multilane Highway Multilane Highway Multilane Highway Two-Lane Highway Two-Lane Highway Two-Lane Highway Two-Lane Highway Two-Lane Highway 65 60 55 50 45 40 35 30 25 20 9.04 10-5 1.39 10-4 2.24 10-4 3.89 10-4 7.48 10-4 Arterial Class I Arterial Class I Arterial Class I Arterial Class II Arterial Class II Arterial Class II Arterial Class III Arterial Class III Arterial Class III Arterial Class IV Arterial Class IV Arterial Class IV Note: N/A = not applicable [please add the following] 0.5 2.0 4.0 1.0 2.0 3.0 3.0 5.0 6.0 6.0 8.0 10.0 This table is provided for the convenience of the analyst and should be considered approimate. Precise values of J can be computed using Equation 30-8. 2.21 10-5 2.04 10-4 1.25 10-3 4.99 10-5 2.00 10-4 7.91 10-4 8.01 10-4 1.78 10-3 3.18 10-3 3.17 10-3 4.99 10-3 7.11 10-3