01590304

Component

Horizontal alignment is a major roadway characteristic used in safety and operational evaluations of many facility types. The Highway Safety Manual (HSM) uses this characteristic in crash prediction models for rural two-lane highways, freeway segments, and freeway ramps/C-D roads. Traffic simulation models use this characteristic in their processes on almost all types of facilities. However, a good portion of roadway databases do not include horizontal alignment data; instead, many contain point coordinate data along the roadways. This data can be used to extract actual horizontal alignment data. Unfortunately, extracting horizontal alignment is a cumbersome and costly process, especially for a database of miles and miles of highways. This research introduces a so called “Quasi-Horizontal alignment” that can be produced easily and automatically from point coordinate data and can be used in the safety and operational evaluations of highways. SHRP 2 Roadway Information Database (RID) for rural two-lane highways in Washington State is used in this study. In the RID geodatabases, only about 5% of the highway sections have actual horizontal alignment data. This paper presents a process through which Quasi-Horizontal alignments are produced from point coordinates along highways by using spreadsheet software such as MS EXCEL. It is shown that the safety and operational evaluations of the highways with Quasi-Horizontal alignments are almost identical to the ones with the actual alignments. In the absence of actual alignment the Quasi-Horizontal alignment can easily be produced from any type of databases that contain highway coordinates such geodatabases and digital maps.

This paper was sponsored by TRB committee ANB20 Standing Committee on Safety Data, Analysis and Evaluation.

01584066

16-1454

English

20p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

Figures; References; Tables

Algorithms; Alignment; Crash risk forecasting; Highway curves; Rural highways

Highway Safety Manual

Data and Information Technology; Highways; I72: Traffic and Transport Planning

Transportation Research Board Annual Meeting 2016 Paper #16-1454

PRP, TRIS, TRB, ATRI

Jan 12 2016 4:38PM