# LAB1 - Highway Capacity Manual 2000 EXAMPLE PROBLEM 1 The...

This preview shows pages 1–3. Sign up to view the full content.

Highway Capacity Manual 2000 Chapter 23 - Basic Freeway Segments 23-18 Example Problems E XAMPLE P ROBLEM 1 The Freeway Existing four-lane freeway, rural area, very restricted geometry, rolling terrain, 70-mi/h speed limit. The Question What is the LOS during the peak hour? The Facts Two lanes in each direction, 5 percent trucks, 11-ft lane width, 0.92 PHF, 2-ft lateral clearance, 1 interchange per Commuter traffic, mile, and 2,000-veh/h peak-hour volume Rolling terrain. (one direction), Comments Assume 0 percent buses and RVs since none are indicated. Assume BFFS of 75 mi/h for rural areas. Assume that the number of lanes does not affect free-flow speed, since the freeway is in a rural area. Assume f p = 1.00 for commuter traffic. Outline of Solution All input parameters are known. Demand is computed in terms of passenger cars per hour per lane, an FFS is estimated, and the LOS is determined from the speed-flow graph. An estimate of passenger-car speed is determined from the graph, and a value of density is calculated using speed and flow rate. The calculation of speed is based on the equation found in Exhibit 23-3. Steps 1. Convert volume (veh/h) to flow rate (pc/h/ln) ( use Equation 23-2 ). v p = V (PHF)(N)(f HV )(f p ) v p = 2,000 (0.92)(2)(f HV )(1.00) 2. Find f HV ( use Exhibit 23-8 and Equation 23-3). f HV = 1 1 + P T (E T – 1) + P R (E R – 1) f HV = 1 1 + 0.05(2.5 – 1) + 0 f HV = 0.930 3. Find v p ( use Equation 23-2 ). v p = 2,000 (0.92)(2)(0.930)(1.00) = 1,169 pc/h/ln 4. Compute free-flow speed ( use Exhibits 23-4, 23-5, 23-6, 23-7, and Equation 23-1 ). FFS = BFFS – f LW – f LC – f N – f ID FFS = 75 – 1.9 – 2.4 – 0.0 – 2.5 FFS = 68.2 mi/h 5. Determine level of service ( use Exhibit 23-2 ). LOS B The Results LOS = B, Speed = 68 mi/h, and Density = 17 pc/mi/ln.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Highway Capacity Manual 2000 23-19 Chapter 23 - Basic Freeway Segments Example Problems Example Problem 1 1 1 + P T (E T – 1) + P R (E R – 1) V or DDHV PHF * N * f HV * f p V or DDHV PHF * N * f HV * f p V or DDHV PHF * N * f HV * f p Analyst ________________________ Highway/Direction of Travel _____________________ Agency or Company ________________________ From/To _____________________ Date Performed ________________________ Jurisdiction _____________________ Analysis Time Period ________________________ Analysis Year _____________________ Operational (LOS) Design (N) Design (v p ) Planning (LOS) Planning (N) Planning (v p ) Volume, V ___________________veh/h Peak-hour factor, PHF _______________ Annual avg. daily traffic, AADT ___________________veh/day % Trucks and buses, P T _______________ Peak-hour proportion of AADT, K ___________________ % RVs, P R _______________ Peak-hour direction proportion, D ___________________ General terrain DDHV = AADT * K * D ___________________veh/h Level Rolling Mountainous Driver type Commuter/Weekday Recreational/Weekend Grade Length _________ mi Up/Down __________ % Lane width ___________________ft f LW _______________mi/h Rt.-shoulder lateral clearance ___________________ft f LC _______________mi/h Interchange density ___________________I/mi f ID _______________mi/h Number of lanes, N ___________________ f N _______________mi/h FFS (measured) ___________________mi/h FFS = BFFS – f LW – f LC – f ID – f N _______________mi/h Base free-flow speed, BFFS ___________________mi/h General Information Site Information Flow Inputs Calculate Flow Adjustments Speed Inputs Calculate Speed Adjustments and FFS LOS and Performance Measures Glossary Factor Location BASIC FREEWAY SEGMENTS WORKSHEET N - Number of lanes S - Speed E R - Exhibits 23-8, 23-10 f LW - Exhibit 23-4 V - Hourly volume D - Density E T - Exhibits 23-8, 23-9, 23-11 f LC - Exhibit 23-5 v p - Flow rate FFS - Free-flow speed f p - Page 23-12 f N -
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern