Evaluation of Variable Advisory Speed Limits in Work Zones, TPF-5(081), 2013

Variable advisory speed limit (VASL) systems could be effective at both urban and rural work zones, at both uncongested and congested sites. At uncongested urban work zones, the average speeds with VASL were lower than without VASL. But the standard deviation of speeds with VASL was higher. The increase in standard deviation may be due to the advisory nature of VASL. The speed limit compliance with VASL was about eight times greater than without VASL. At the congested sites, the VASL were effective in making drivers slow down gradually as they approached the work zone, reducing any sudden changes in speeds. Mobility-wise the use of VASL resulted in a decrease in average queue length, throughput, number of stops, and an increase in travel time. Several surrogate safety measures also demonstrated the benefits of VASL in congested work zones. VASL deployments in rural work zones resulted in reductions in mean speed, speed variance, and 85th percentile speeds downstream of the VASL sign. The study makes the following recommendations based on the case studies investigated: 1. The use of VASL is recommended for uncongested work zones to achieve better speed compliance and lower speeds. Greater enforcement of regulatory speed limits could help to decrease the standard deviation in speeds; 2. The use of VASL to complement the static speed limits in rural work zones is beneficial even if the VASL is only used to display the static speed limits. It leads to safer traffic conditions by encouraging traffic to slow down gradually and by reminding traffic of the reduced speed limit. A well-designed VASL algorithm, like the P5 algorithm developed in this study, can significantly improve the mobility and safety conditions in congested work zones. The use of simulation is recommended for optimizing the VASL algorithms before field deployment.

Cooperatives and Contracting in Agriculture: The Case of West Liberty Foods, October 2005

The West Liberty Foods turkey cooperative was formed in 1996 to purchase the assets and assume operations of Louis Rich Foods (an investor-owned processing rm), which, at the time, announced the imminent shutdown of its West Liberty, Iowa, processing facility. We study the creation and performance of this �new generation� cooperative using eld interviews with grower members and company management. We describe changes, before and after the buyout, in the contractual apparatus used for procuring live turkeys, and in the communication requirements, work expectations, and nancial positions of growers. During the private ownership period, most of the inputs (except labor and facilities) were provided by the rm; there was substantial supervision of the growers' actions; growers faced little price and production risk; and growers' equity was due largely to ownership of land and other farm assets. Our interviews reveal that, after cooperative formation, growers were exposed to considerable additional risk; monitoring of growers by the rm was less intensive; grower time and effort commitments to turkey production increased substantially; and a signicant fraction of rm (cooperative) equity came from growers' willingness to leverage their farm and personal assets (and hence indirectly their existing relationships with local lenders). We argue that some of these changes are consistent with a nancial contract where asset pledging and its corollary risk generate higher work effort by growers and a reduction in agency rents. These economies likely compensate for an organizational deadweight loss traditionally associated with cooperative governance.

Road Safety Audit for IA 28 from the South Corporate Limits of Norwalk in Warren County through the IA 5 Interchange in Polk County, Iowa, November 2012

In response to local concerns, the Iowa Department of Transportation (DOT) requested a road safety audit (RSA) for the IA Highway 28 corridor through the City of Norwalk in Warren County, Iowa, from the south corporate limits of Norwalk through the IA 5 interchange in Polk County, Iowa. The audit included meeting with City staff to discuss concerns, review crash history and operational issues, observe the route under daylight and nighttime conditions, and analyze available data. This report outlines the findings and recommendations of the audit team for addressing the safety concerns and operational matters along this corridor.

Road Safety Audit for County Road X-37, from the Intersection of G-62 to the East Corporate Limits of Columbus City in Louisa County, Iowa, 2009

A road safety audit was conducted for a 7.75 mile section of County Road X-37 in Louisa County, Iowa. In 2006, the average annual daily traffic on this roadway was found to be 680 vehicles per day. Using crash data from 2001 to 2007, the Iowa Department of Transportation (Iowa DOT) has identified this roadway as being in the highest 5% of local rural roads in Iowa for single-vehicle runoff- road crashes. Considering these safety data, the Louisa County Engineer requested that a road safety audit be conducted to identify areas of safety concerns and recommend low-cost mitigation to address those concerns. Staff and officials from the Iowa DOT, Governor’s Traffic Safety Bureau, Federal Highway Administration, Institute for Transportation, and local law enforcement and transportation agencies met to review crash data and discuss potential safety improvements to this segment of X-37. This report outlines the findings and recommendations of the road safety audit team to address the safety concerns on this X-37 corridor and explain several selected mitigation strategies.

Road Safety Audit for County Road H-46 from Redwood Avenue to the Southerly Corporate Limits of Fairfield in Jefferson County, Iowa, 2010

Jefferson County Road H-46 from Redwood Avenue to the southeast corporate limits (SCL) of Fairfield, Iowa, is a paved roadway approximately 6.5 miles long made of asphaltic concrete pavement with curvilinear alignment. The roadway consists of a 22 ft wide pavement, last overlaid in 2002, with 3 to 4 ft wide earth shoulders. Traffic estimates indicated volumes ranging from 500 to 1,590 vehicles per day, with numbers increasing as the route nears Fairfield. This roadway was found to be among the highest 5 percent of similar Iowa roadways in terms of severity of run-off-road crashes. In response, Iowa Department of Transportation (Iowa DOT) requested a road safety audit to examine the roadway and suggest possible mitigation. Representatives from the Iowa DOT, Federal Highway Administration, Institute for Transportation, local law enforcement, and local government met to review crash data and discuss potential safety improvements to this segment H-46. This report outlines the findings and recommendations of the road safety audit team for addressing the safety concerns on this roadway.

Road Safety Audits for County Road X-23 from IA 2 to the South Corporate Limits of West Point and for County Road W-62 from US 218 to IA 27 in Lee County, Iowa, 2010

On October 20–21, 2009, two road safety audits were conducted in Lee County, Iowa: one for a 6 mile section of County Road X-23 from IA 2 to the south corporate limits of West Point and one for a 9.7 mile section of County Road W-62 from US 218 to IA 27. Both roads have high severe crash histories for the years of 2001 through 2008. Using these crash data, the Iowa Department of Transportation (Iowa DOT) has identified County Road X-23 as being in the top 5 percent of similar roads for run-off-road crashes. The Iowa DOT lists County Road W-62 as a high-risk rural road that has above-average crash numbers and is eligible for funding under the Federal High-Risk Rural Road Program. Considering these issues, the Lee County Engineer and Iowa DOT requested that road safety audits be conducted to address the safety concerns and to suggest possible mitigation strategies.

Road Safety Audit for James Avenue NW and 250th Street NW, from the North Corporate Limits of Tiffin to I-380, in Johnson County, Iowa, 2010

To address safety concerns on James Avenue NW and 250th Street NW, from the North Corporate Limits (NCL) of Tiffin, north and east to I-380 (at North Liberty), the Johnson County engineer requested a road safety audit (RSA). The audit was conducted on September 1, 2010, through a program supported by the Office of Traffic and Safety at the Iowa Department of Transportation (DOT). This road is a seal-coated roadway, about 25-ft wide, but with only about 0-1 ft of earth shoulders. According to 2006 Iowa DOT estimates, traffic volume is about 820 vehicles per day, north from Tiffin to a commercial entrance on 250th Street, then increasing to 2,990 vehicles per day to the on-ramp of Interstate 380 (I-380). Local traffic uses this road as a short-cut to Cedar Rapids, North Liberty, and the I-380/I-80 interchange (to avoid congestion on IA 965). This report outlines the findings and recommendations of the road safety audit team for addressing the safety concerns on this roadway.

Retail trading areas in Des Moines, Henry, and Lee counties : a study / by the Committee on Business and Industry, Iowa State Planning Board, 1936

This study provides information on retail trade and market surveys in Des Moines, Henry and Lee Counties in Iowa. Maps and tables are included. Transportation facilities, sources of income, trading areas, banking changes, shopping centers and other factors that impact retail trade are discussed.