Traffic Volume Introduction

INTRODUCTION

Traffic Volume Studies A traffic study consists of a comprehensive investigation of existing physical and operating conditions. Analysis of the study data provides insight into possible remedial measures, if any. Remedial measures may include various traffic control measures, such as speed zoning, channelization, signing, traffic signals, safety lighting, or a combination of these. Engineers often use counts of number of vehicles or Pedestrians passing a point, entering an intersection, or Using a particular facility such as travel lane, crosswalk Or sidewalk. Counts are usually samples of actual volumes, although continuous counting is also sometimes performed. Sampling periods may range from a few minutes to a month or more. The measurement of traffic volumes is one of the most basic functions of highway planning and management. Traffic volume counts provide the most commonly employed measure of roadway usage and are needed for the majority of traffic engineering analyses. While a number of traffic volume statistics are used in traffic engineering analyses, two are of primary interest for the design of a statewide traffic monitoring program: annual average daily traffic (AADT) and average daily vehicle distance traveled (DVDT).
AADT describes the number of vehicles that traverse a road at a specific point on the road system. DVDT describes the travel usage of an entire segment of roadway. DVDT is computed by multiplying the length of a roadway segment by its AADT. AADT is the primary traffic input to most traffic engineering analyses. DVDT is the primary measure for describing roadway usage for an entire system or network of roads.
The primary objective of this section is to describe how to structure statewide traffic monitoring programs to compute AADT and DVDT