Guidelines of roadway undulation measurements with straightedges

Chen-Ming Kuo, Ting Yi Tsai

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Straightedge is still widely adopted as a simple and reliable tool in pavement smoothness measurements, although rolling profilers have become more and more popular. If measured and interpreted correctly, the data collected with a straightedge is able to provide not only undulation depth but also profile wavelength. This study examines the basic features of measurements of roadway undulations with straightedges as well as the critical vibration frequencies for riding comfort. A universal gain curve is proposed to adjust measurements with various straightedges. A vehicle-pavement coupled system is formulated to find the natural frequencies of a vehicle, wheel axle, and pavement. The system also determines the wavelengths critical to riding comfort on roadways. Analysis with the coupled system shows that the vibrations critical to riding comfort may be magnified and transmitted through the wheel axle. The research suggests the suitable straightedge for specific wavelengths. The 3 meter straightedge is recommended on freeways with speed limits over 100 km/h, whereas the 1 meter straightedge is more suitable for urban streets to assure correct amplitudes of the critical waviness to riding comfort. Measurement interval is critical to the resolution of profile wavelengths. It is suggested that the measurement interval not exceed half of the critical wavelength.

Original languageEnglish
Pages (from-to)62-67
Number of pages6
JournalInternational Journal of Pavement Research and Technology
Issue number1
Publication statusPublished - 2012 Jan 30

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Mechanics of Materials


Dive into the research topics of 'Guidelines of roadway undulation measurements with straightedges'. Together they form a unique fingerprint.

Cite this