Highway Engineering Traffic Engineering Studies

Group Members Matric Number

AFANDI BIN SAFI A141506

AMIRUL ANWAR BIN MOHD SOLONG A139607

MOHD AZMAN BIN SAMER A141428

MUHAMMAD TAUFIQ BIN OTHMAN A141468

SPOT SPEED STUDIES

Location

• Basic data collection

• Speed trend analyses

• Specific traffic engineering problem

Time of Day and Duration

• Free-flowing or off-peak hour

• Nature of complaints

• >=1hour, >=30 vehicles

Sample Size

• Average Speed

• Median Speed• Modal Speed• The ith-

percentile Spot Speed

• Pace• Standard

Deviation of Speeds

To estimate speed distribution of vehicles in a stream of traffic at particular location on a highway.

MethodsManual

Pavement markingsEnoscope or Mirror box

AutomaticRoad detectors•Pneumatic road tubes•Inductive loop

Radar-Based Traffic SensorsElectronic-Principle Detectors

SPOT SPEED STUDIES

SPOT SPEED STUDIES

• spot speed studies are usually taken only from a sample of vehicles

• using the section of the highway on which the study is conducted.

• These data are used to determine the speed characteristics of the whole population of vehicles.

• Most commonly used is the frequency distribution table

SPOT SPEED STUDIES

Other Forms of Presentation and Analysis of Speed Data

• May require a more complicated presentation and analysis of the speed data

• May be necessary for the speed data to be fitted into a suitable theoretical frequency distribution. methods of hypothesis testing: Chi square testing

Comparison of mean speed

• Sometimes necessary to know if there is significant difference between the mean speeds of two spot speed studies.

VOLUME STUDIES

Traffic Volume Data Presentation

1.Traffic flow map - Show individual routes. Volume of traffic is represented by the width of a band.

2. Intersection summary sheets - Graphic representations of the volume and directions of all traffic movement at the intersection.

3.Time-based distribution charts - Show hourly, monthly and annual variation in traffic volume in an area or a highway.

4.Summary Tables - Summary of traffic volume data such as PHV, Vehicle Classification (VC) and ADT in tabular form.

VOLUME STUDIES

Traffic Volume Characteristic

• Based on regular observation of traffic volumes over the years.

• This variation is repetitive and rhythmic.

• Taken into consideration when traffic counts are being planned.

• Factors: Weather and peak hours.

.

VOLUME STUDIESSample Size and Adjustment of Periodic Counts

• Minimum sample size depends on the precision level desired (95-5 is commonly used).

• When sample size < 30, selection of counting station is random.

• Minimum sample equation,

VOLUME STUDIESSample Size and Adjustment of Periodic Counts

• Adjustment of periodic counts,