Evaluation of Lime as an Additive to Soil-Asphalt Stabilization, HR-1, Progress Report, 1961

This report presents the results of a limited investigation of the use of lime as an auxiliary additive for improving the stabilization of soils with cutback asphalts. It is felt that the data obtained presents additional information on the subject of asphalt stabilization

In-Pavement Pedestrian Flasher Evaluation: Cedar Rapids, Iowa, 2004

Numerous strategies have been experimented with nationwide in an attempt to reduce the overall number of pedestrian-vehicle crashes, especially in instances where improper crossing or failure to yield was the proximate cause of the crash. Some of these measures include overhead signs, flashing warning beacons, advanced crossing signs, more visible pavement markings, in-street “Yield to Pedestrian” signs, and more recently, in-pavement flashing lights. Pedestrian safety has been a key issue for the City of Cedar Rapids, Iowa, in particular at non-controlled intersections and mid-block crossings. In 2002, the city council gave preliminary approval to implement a pedestrian-actuated overhead flasher system in conjunction with an in-pavement flasher system at the intersection of 1st Avenue NE and 4th Street NE in the downtown central business district. This location is uncontrolled and has several elements that can create conflicts between pedestrians, vehicles, and trains that service local industry. This report summarizes the results from a small-scale study completed by CTRE to evaluate the effectiveness of the in-pavement flasher system installed in downtown Cedar Rapids. The installation of in-pavement flashing warning lights at the pedestrian crosswalk at this site has had a net positive effect on the safety characteristics of the location. The results of this study show a marked improvement in motorist compliance with the state law requiring that motorists yield to pedestrians in the crosswalk. The pedestrian and motorist surveys show that both groups felt the in-pavement flashing lights have increased motorist awareness, especially at night. The data indicate the in-pavement flashing warning lights improved the motorists' response to pedestrians in the area, and that the system could be operational throughout summer and winter conditions.

Managing Decisions Regarding Rural Expressway Routes and Associated Highway Bypasses, 2009

For several years, the Iowa Department of Transportation has constructed bypasses along rural highways. Most bypasses were constructed on the state’s Commercial Industrial Network (CIN). Now that work on the CIN has been completed and the system is open to traffic, it is possible to study the impacts of bypasses. In the past, construction of highway bypasses has led community residents and business people to raise concerns about the loss of business activity. For policy development purposes, it is essential to understand the impacts that a bypass might have on safety, the community, and economics. By researching these impacts, policies can be produced to help to alleviate any negative impacts and create a better system that is ultimately more cost-effective. This study found that the use of trade area analysis does not provide proof that a bypass can positively or negatively impact the economy of a rural community. The analysis did show that, even though the population of a community may be stable for several years and per capita income is increasing, sales leakage still occurs. The literature, site visits, and data make it is apparent that a bypass can positively affect a community. Some conditions that would need to exist in order to maximize a positive impact include the installation of signage along the bypass directing travelers to businesses and services in the community, community or regional plans that include the bypass in future land development scenarios, and businesses adjusting their business plans to attract bypass users. In addition, how proactive a community is in adapting to the bypass will determine the kinds of effects felt in the community. Results of statistical safety analysis indicate that, at least when crashes are separated by severity, bypasses with at-grade accesses appear to perform more poorly than either the bypasses with fully separated accesses or with a mix of at-grade and fully separated accesses. However, the benefit in terms of improved safety of bypasses with fully separated accesses relative to bypasses with a mixed type of accesses is not statistically conclusive.

Iowa Study of No Passing Zone Signing, 1962

This report is compiled from data gathered by interviewing motorists to sample their opinion of Iowa's method of supplementing the yellow barrier line pavement marking of no passing zones on primary highways with yellow pennant shaped "No Passing Zone" signs mounted on the left shoulder of the highway. The effective designation of no passing zones is one form of control that can contribute to a reduction in the number of fatal high-speed head-on collisions resulting from passing in areas which do not afford sufficient sight distance of approaching traffic. It is the purpose of this report to present an evaluation of the Iowa "No Passing Zone" sign by individuals from all states who have traveled on Iowa's primary highways and who must obey the no passing zone restrictions and be warned by this sign of the presence of the zones. The "No Passing Zone" sign was formulated and approved by the Governor's Safety Committee a short time prior to the experimental erection of the signs. The Governor's Safety Committee adopted this sign as they felt that such a sign should be distinctive (not similar to any other type of sign) and easily visible to a driver attempting a passing maneuver.