PE Exam - Transportation Depth, PE Transportation

85th Percentile

HCM vol. 3 Chapter 19 - 85th percentile speed of the observed speeds is typically set as the speed limit

Free Flow Speed (FFS) / LOS

HCM Ch.12-2 (Freeway, Multilane Hwy)

HCM Ch.15 (2-lane Hwy)

Freeway FFS - f(LW)

HCM Exhibit 12-20

Minimum Acceleration Length on-ramp

GDHS Table 10-4

Freeway FFS - f(LC)

HCM Exhibit 12-22

Freeway FFS (ideal condition)

75.4 mph

Freeway Service Flow Rate

HCM Eqn 12-9

Signalized Intersections

HCM Chapter 19 and 31

Peak Hour Factor

PHF = V/(V15 * 4)

Freeway Service Flow Rate - F(hv)

HCM Eqn 12-10, 15-4

Freeway Service Flow Rate - F(hv) ---> E(T) and E(R)

For level terrains, HCM Exhibit 12-25

For grades, HCM Exhibit 12-26 through 28

Freeway FFS- TRD

# Ramps / # miles

Freeway Problem finding LOS

1. Find FFS

2. Find Service Rate

3. Find Density = Service Rate / FFS

4. Use the HCM Exh 12-15 (Freeway LOS) to find the corresponding LOS to the calculated density.

Freeway Density and LOS

HCM Eqn 12-11, Exhibit 12-15 (for LOS determination)

2-Lane Highway LOS Determination by Class

HCM Exh. 15-3

2-Lane Highway - Service Flow (Demand Volumes)

HCM Eqn 15-3

2-Lane Highway - Service Flow (Demand Volumes) --> f(g)

Grade Adjustment Factor HCM Exh 15-9, 15-10

2-Lane Highway - FFS

HCM Eqn 15-2

2-Lane Highway - FFS ---> f(LS)

HCM Exh 15-7

2-Lane Highway - Service Flow (Demand Volumes) --> f(hv)

Heavy vehicle adjustments HCM Eqn 15-4, 15-5

Intersection Capacity - Lane Group Capacity

HCM Ch.19

Intersection Capacity - Sat Flow Rate

HCM Ch.19

Intersection Capacity - Delay

HCM Ch.19

Intersection Capacity - Degree of Saturation

HCM Ch.19

g ---> acceleration due to gravity

32.2 ft/s^2

Highway Safety Analysis

HSM Ch.9

Two-Way Stop (TWSC) Intersections

HCM Chapter 20 and 32

All-Way Stop-Controlled (AWSC) Intersections

HCM Chapter 21 and 32

Two-Way Stop (TWSC) Intersections Methodology (13 Steps)

HCM Chapter 20-11

a ---> deceleration rate for vehicles (for yellow interval)

10 ft/s^2 (HCM Chapter 19) for Yellow (Y) equation

Vehicle Length

20ft typical

Taper Length

MUTCD 6D-4

Pedestrian Service Time

HCM Chapter 19 (Eq 19-65)

Cycle length (Signalized intersection)

HCM Chapter 19 (equation 19-30)

Platoon Ratio (Signalized intersection)

HCM Chapter 19 (exhibit 19-13)

Roundabouts

HCM Chapter 22

Freeway Weaving Segments

HCM Chapter 13

Freeway Merge and Diverge Segments

HCM Chapter 14

Interchange Configurations (diamond, cloverleaf, trumpet & rotary)

AASHTO Green Book - Chapter 10

Acceleration and Deceleration Lengths (parallel/ taper...)

AASHTO Green Book - Chapter 10 (table 10-4, 10-6)

Signal Spacing

HCM Chapter 18 (page 18-29)

Gravity Model

NCEES Handbook

Crash Rate, Traffic Safety

Highway Safety Manuel (HSM) Chapter 4

Crashes on Roadway Segments

Highway Safety Manuel (HSM) Chapter 6

ON-street Pedestrians

HCM Chapter 18

OFF-street Pedestrians

HCM Chapter 24

Shared Use Paths (Bikes and Pedestrians)

HCM Chapter 24

Safety Performance Function (SPF)

Highway Safety Manual (HSM) Chapter 11

Rural Multilane Highways

HSM Chapter 11 (table 11-2)

headway

time between successive vehicles [sec / veh]. measured between from the front to front

Urban and Suburban Arterials

HSM Chapter 12 (table 12-2)

Intersections (safety, crashes...)

HSM Chapter 14

Roadside Hazard Rating

HSM Chapter 13

Human Factors (safety...)

HSM Chapter 2

Accident rate for rural areas (driveways per mile)

AASHTO Green Book

Bus Level of Service (LOS)

HCM Chapter 18 (transit LOS)

Intersection Conflict Points

AASHTO Green Book

Density =

flow rate [vphpl] / speed [mph]

Time mean speed

average speed of vehicles passing on a road

NCEES pg 267 - sum(speeds) / n

space mean speed

average speed of all vehicles occupying a given section of highway

gap

distance OR time gap between the back of the leading to the front of the following (not including the vehicle length)

weaving segment

HCM Vol 2 Ch 13

headway =

(3600 sec/hr) / v

headway =

spacing / S

jam density

density at 0 speed

AADT =

total yearly volume / 365

Directional Factor

peak dir hourly vol / 2 way hourly volume

Simple Hori Curve

arc of a circle is tangential

Compound Hori Curve

2 or more simple curves with varying radius

Reverse Hori Curve

2 circular arcs center opp.

Spiral Hori Curve

varying radius

Startup loss time for a traffic signal

2 sec

Pedestrian walk pace

3.5 ft/sec

1 interchange means

2 ramps ( 1 on 1 off)

Signalized intersection

HCM Vol 3 Ch 19

Freeway ramps

HCM Vol 2 Ch 14

Urban motorized veh and pedestrians bicycle transit

HCM Vol 3 Ch 18

2 way side streets

HCM Vol 3 Ch 20

Ramp terminal and alternative intersections

HCM Vol 3 Ch 23

crash reduction capabilities

crash expected to change due to countermeasure

CRF

crash reduction factor

CMF

crash modification factor

PDO

property damage only

horizontal sightline break reaction time typically (GDHS)

2.5 sec

EDPO

equivalent prpperty damage only

degree of curve

amount of interior angle req to cover a 100' distance along arc

interior angle

angle formed between PC to PI and PI to PT

PC =

PI - T

PT =

PC + L

horizontal sightline deceleration rate typically (GDHS)

11.2 ft/s^2

tailgate typically (h2 = object height) for sight distance

2' off ground (GDHS 3.4.6.4)

reaction time for signals

1 sec

HSO is calculated from

drivers position eyes to object

Driver's eye height h1 (for sight disctance calc)

8ft (GDHS 3.4.6.4)

Barrier Design

RDG Ch 5-9

3 leg intersection has _ conflict points

9

4 leg intersection has _ conflict points

32

types of conflict points

diverging merging crossing

roundabout 3 leg has _ conflict points

6

roundabout 4 leg has _ conflict points

8