InTrans / Sep 22, 2021

Traffic studies are useful tool for local agencies

Virtual workshop offers a refresher in data collection, analysis

“Just like riding a bike” is a common adage to suggest how easily muscle memory kicks in when performing tasks that we do infrequently or irregularly, but reflex only works so well and usually only for simple chores.

When it comes to complex actions, a better adage may be, “Practice makes perfect.”

That’s why LTAP Safety Circuit Rider David Veneziano led a pilot workshop on completing traffic studies back in March. The workshop was held virtually and is still available for viewing here.

As part of a now-complete research project, Veneziano had asked local agencies to complete a speed study to borrow a speed feedback sign, and the question that came back as often as not was “How would I do that?”

The response reminded him that these studies are often taught in college courses or conducted by local agencies on such an infrequent basis that many could use a refresher.

The workshop covered how to conduct traffic volume, speed, sight distance, curve speed, and intersection traffic control studies to provide a better understanding of the approaches to data collection and basic data evaluation and presentation knowledge.

“Data collection provides the basis for identifying problems, quantifying the impacts of changes, determining the nature of magnitude of improvements, or confirming a hypothesis,” Veneziano said. “Valid results require careful, standardized collection and analysis.”

He added, “When you’re in doubt, though, it’s better to collect more data than it is to collect less data.”

Though the virtual workshop discusses the options and aspects of the various studies, Veneziano said they all have some common aspects, equipment, and terminology. He stressed the first step should always be field safety.

“The first and foremost that I will stress is safety, both yours and your coworkers’ safety when you’re out in the field,” Veneziano said. “No data collection is worth losing your life over.”

He said anyone who cannot conduct a study safely may need to investigate setting up temporary traffic control. Veneziano also said that practicing before going out into the field is key to ensuring that the equipment, if applicable, is working and that staff feels comfortable while working in live traffic conditions without having to troubleshoot.

In addition to the webinar, the Iowa DOT also has a traffic engineering assistance program that smaller local agencies can use. More details on the program is available here.

Recommended reading:

Did you know?

Iowa LTAP has an equipment loan program that includes two pieces of equipment useful in completing traffic studies and one that can aid after a speeding issue has been determined from a study. These items include the following:

  • Radar recorders. These assist in collecting bi-directional data on vehicle speed, length, gap and volume. They mount to utility poles and provide a non-invasive way to collect a variety of traffic data, particularly on unpaved roadways.
  • Digital ball banks. These can be used to assist in completing an engineering study to determine advisory speeds in curves. The unit provides measurements of the degree of bank collected when passing through a curve to assist in determining whether an advisory speed plaque is recommended or required.
  • Trailer-mounted speed feedback signs. LTAP has two trailer-mounted signs available, and no prior speed study is required to borrow them. These signs can be used to address speeding, as well as for other issues (e.g. special events, etc.).

For additional details about these and other pieces of equipment or to make a request for them, click here or contact David Veneziano at or 515-294-5480.