Liability and Traffic Control Considerations for Low Water Stream Crossings, HR-218, 1981

The current shortage of highway funds precludes the immediate replacement of most of the bridges that have been evaluated as structurally deficient or functionally obsolete or both. A low water stream crossing (LWSC) affords an economical alternative to the replacement of a bridge with another bridge in many instances. However, the potential liability that might be incurred from the use of LWSCs has served as a deterrent to their use. Nor have guidelines for traffic control devices been developed for specific application to LWSCs. This research addressed the problems of liability and traffic control associated with the use of LWSCs. Input to the findings from this research was provided by several persons contacted by telephone plus 189 persons who responded to a questionnaire concerning their experience with LWSCs. It was concluded from this research that a significant potential for accidents and liability claims could result from the use of LWSCs. However, it was also concluded that this liability could be reduced to within acceptable limits if adequate warning of the presence of an LWSC were afforded to road users. The potential for accidents and liability could further be reduced if vehicular passage over an LWSC were precluded during periods when the road was flooded. Under these conditions, it is believed, the potential for liability from the use of an LWSC on an unpaved, rural road would be even less than that resulting from the continuing use of an inadequate bridge. The signs recommended for use in advance of an LWSC include two warning signs and one regulatory sign with legends as follows: FLOOD AREA AHEAD, IMPASSABLE DURING HIGH WATER, DO NOT ENTER WHEN FLOODED. Use of the regulatory sign would require an appropriate resolution by the Board of Supervisors having responsibility for a county road. Other recommendations include the optional use of either a supple mental distance advisory plate or an advisory speed plate, or both, under circumstances where these may be needed. It was also recommended HR-218 Liability & Traffic Control Considerations for Low Water Stream Crossings that LWSCs be used only on unpaved roads and that they not be used in locations where flooding of an LWSC would deprive dwelling places of emergency ground access.

Construction and Maintenance Practices to Minimize the Potential Liability of Counties for Roads in Rural Subdivisions, HR-221, 1981

In an earlier research project, HR-204, the magnitude and nature of highway related tort claims against counties in Iowa were investigated. However, virtually all of the claims identified in that research resulted from incidents that occurred in areas with predominantly agricultural land use. With recent increases in the rural non-farm population, many traditionally urban problems are also appearing in built-up areas under county jurisdiction. This trend is expected to continue so that counties must anticipate a change in the nature of the tort claims they will encounter. Problems that heretofore have been unique to cities may become commonplace in areas for which counties are responsible. The research reported here has been directed toward an investigation of those problems in rural subdivisions that lead to claims growing out of the provision of highway services by counties. Lacking a sufficient database among counties for the types of tort claims of interest in this research, a survey was sent to 259 cities in Iowa in order to identify highway related problems leading to those claims. The survey covered claims during a five year period from 1975 to 1980. Over one-third of the claims reported were based on alleged street defects. Another 34 percent of the claims contained allegations of damages due to backup of sanitary sewers or defects in sidewalks. By expanding the sample from the 164 cities that responded to the survey, it was estimated that a total of $49,000,000 in claims had been submitted to all 259 cities. Over 34% of this amount resulted from alleged defects in the use of traffic signs, signals, and markings. Another 42% arose from claims of defects in streets and sidewalks. Payments in settlement of claims were about 13.4% of the amount asked for those claims closed during the period covered by the survey. About $9,000,000 in claims was pending on June 30, 1980 according to the information furnished. Officials from 23 cities were interviewed to provide information on measures to overcome the problems leading to tort claims. On the basis of this information, actions have been proposed that can be undertaken by counties to reduce the potential for highway-related claims resulting from their responsibilities in rural subdivisions and unincorporated communities. Suggested actions include the eight recommendations contained in the final report for the previous research under HR-204. In addition, six recommendations resulted from this research, as follows: 1. Counties should adopt county subdivision ordinances. 2. A reasonable policy concerning sidewalks should be adopted. 3. Counties should establish and implement a system for setting road maintenance priorities. 4. Counties should establish and implement a procedure for controlling construction or maintenance activities within the highway right of way. 5. Counties should establish and implement a system to record complaints that are received relating to highway maintenance and to assure timely correction of defective conditions leading to such complaints. 6. Counties should establish and implement a procedure to ensure timely advice of highway defects for which notice is not otherwise received.

Maintaining Iowa's Secondary Road Environment, HR-289, 1989

The Iowa counties have been successful in maintaining a good roadway environment on our 90,000 mile secondary road system. However, county highway personnel must remain vigilant in detecting, discovering and correcting potential problems if our roads are to remain so. This presentation was developed for those county personnel who work and travel on secondary roads. The presentation discusses things county personnel can look for during their daily operations which could possibly create a potential problem. If these situations are uncovered and corrected in a timely manner, our secondary road system will be maintained in an appropriate manner.

Performance of Various Thicknesses of P.C. Concrete Secondary Pavement, HR-9, 1979

In 1951 Greene County and the Iowa Highway Research Board paved County Road E-33 from Iowa Highway No. 17 (now Iowa 4) to Farlin with various thicknesses [ranging from 4.5 in. (11.4 cm) to 6 in. (15.2 cm)] of portland cement concrete pavement. The project, designated HR-9, was divided into ten research sections. This formed pavement was placed on the existing grade. Eight of the sections were non-reinforced except for centerline tie bars and no contraction joints were used. Mesh reinforcing and contraction joints spaced at 29 ft 7 in. (9.02 m) intervals were used in two 4.5-in. (11.4-cm) thick sections. The concrete in one of the sections was air entrained. Signs denoting the design and limits of the research sections were placed along the roadway. The pavement has performed well over its 28-year life, carrying a light volume of traffic safely while requiring no major maintenance. The 4.5-in. (11.4-cm) thick mesh-reinforced pavement with contraction joints has exhibited the best overall performance.

Development of an Economic Dust Palliative for Limestone Surfaced Secondary Roads, HR-297, 1990

This research project was directed at laboratory and field evaluation of sodium montmorillonite clay (bentonite) as a dust palliative for limestone surfaced secondary roads. It had been postulated that the electrically charged surfaces of the clay particles could interact with the charged surfaces of the limestone and act as a bonding agent to agglomerate fine (-#200) particulates and also to band the fine particulates to larger (+#200) limestone particles. Laboratory testing using soda ash dispersed bentonite treatment of limestone fines indicated significant improvement of compressive strength and slaking characteristics. It was recommended that the project proceed to field trials and test roads were constructed in Dallas and Adair counties in Iowa. Soda ash dispersed bentonite solutions can be field mixed and applied with conventional spray distribution equipment. A maximum of 1.5% bentonite(by weight of aggregate)can be applied at one time. Higher applications would have to be staged allowing the excess moisture to evaporate between applications. Construction of higher application treatments can be accomplished by adding dry bentonite to the surfacing material and then by dry road mixing. The soda ash water solution can then be spray applied and the treated surfacing material wet mixed by motor graders to a consistency of 3 to 4 inch slump concrete. Two motor graders working in tandem can provide rapid mixing for both methods of construction. Calcium and magnesium chloride treatments are 2 to 3 times more effective in dust reduction in the short term (3-4 months) but are prone to washboarding and potholing due to maintenance restrictions. Bentonite treatment at the 2-3% level is estimated to provide a 30-40% dust reduction over the long term(18-24 months). Normal maintenance blading operations can be used on bentonite treated areas. Vehicle braking characteristics are not adversely affected up to the 3.0% treatment level. The bentonite appears to be functioning as a banding agent to bind small particulates to larger particles and is acting to agglomerate fine particles of limestone. This bonding capability appears recoverable from environmental effects of winter, and from alternating wet and dry periods. The bentonite appears to be able to interact with new applications of limestone maintenance material and maintains a dust reduction capability. Soda ash dispersed bentonite treatment is approximately 10 times more cost effective per percent dust reduction than conventional chloride treatments with respect to time. However,the disadvantage is that there is not the initial dramatic reduction in dust generation as with the chloride treatment. Although dust is reduced 30-40% after treatment there is still dust being generated and the traveling public or residents may not perceive the reduction.

Bentonite Treatment for Economical Dust Reduction on Limestone Surfaced Secondary Roads, HR-351, 1995

This research project was directed at laboratory and field evaluation of sodium montmorillonite clay (Bentonite) as a dust palliative for limestone surfaced secondary roads. It was postulated that the electrically charged surfaces (negative) of the clay particles could interact with the charged surfaces (positive) of the limestone and act as a bonding agent to agglomerate fine (-#200) particulates, and also to bond the fine particulates to larger (+#200) limestone particles. One mile test roads were constructed in Tama, Appanoose, and Hancock counties in Iowa using Bentonite treatment levels (by weight of aggregate) ranging from 3.0 to 12.0%. Construction was accomplished by adding dry Bentonite to the surfacing material and then dry road mixing. The soda ash/water solution (dispersing agent) was spray applied and the treated surfacing material wet mixed by motor graders to a consistency of 2 to 3 inch slump concrete. Two motor graders working in tandem provided rapid mixing. Following wet mixing the material was surface spread and compacted by local traffic. Quantitative and qualitative periodic evaluations and testing of the test roads was conducted with respect to dust generation, crust development, roughness, and braking characteristics. As the Bentonite treatment level increased dust generation decreased. From a cost/benefit standpoint, an optimum level of treatment is about 8% (by weight of aggregate). For roads with light traffic, one application at this treatment level resulted in a 60-70% average dust reduction in the first season, 40-50% in the second season, and 20-30% in the third season. Crust development was rated at two times better than untreated control sections. No discernible trend was evident with respect to roughness. There was no evident difference in any of the test sections with respect to braking distance and braking handling characteristics, under wet surface conditions compared to the control sections. Chloride treatments are more effective in dust reduction in the short term (3-4 months). Bentonite treatment is capable of dust reduction over the long term (2-3 seasons). Normal maintenance blading operations can be used on Bentonite treated areas. Soda ash dispersed Bentonite treatment is estimated to be more than twice as cost effective per percent dust reduction than conventional chloride treatments, with respect to time. However, the disadvantage is that there is not the initial dramatic reduction in dust generation as with the chloride treatment. Although dust is reduced significantly after treatment there is still dust being generated. Video evidence indicates that the dust cloud in the Bentonite treated sections does not rise as high, or spread as wide as the cloud in the untreated section. It also settles faster than the cloud in the untreated section. This is considered important for driving safety of following traffic, and for nuisance dust invasion of residences and residential areas. The Bentonite appears to be functioning as a bonding agent.

Soil Erosion Control for Secondary Roads, HR-155

Research project HR-155 was initiated to study soil erosion problems along the secondary road system in Iowa and to find a substitute for straw for the control of soil erosion during the period of seed establishment. Accordingly, six field research sites were established to test the ability of commercial soil conditioners to control soil erosion. The six field research sites were selected on the basis of terrain and type of soil material exposed on the cut-slope areas.

Skid Resistance of the Secondary Road System in Iowa, MLR-77-1, 1977

The Iowa Department of Transportation has been conducting skid resistance tests on the paved secondary system on a routine basis since 1973. This report summarizes the data obtained through 1976 on 10,101 miles in 95 of the 99 counties in Iowa. A summary of the skid resistance on the secondary system is presented by pavement type and age. The data indicates that the overall skid resistance on this road system is excellent. Higher traffic roads (over 1000 vehicles per day) have a lower skid resistance than the average of the secondary roads for the same age and pavement type. The use of non-polishing aggregates in asphaltic concrete paving surface courses and transverse grooving of portland cement concrete paving on high traffic roads is recommended. The routine resurvey of skid resistance on the secondary road system on a 5-year interval is probably not economically justified and could be extended to a 10-year interval.

Surface Improvement and Dust Palliation of Unpaved Secondary Roads and Streets, HR-151, 1973

As of December 31, 1970 there were 57,270 miles of Local Secondary roads and 32,958 miles of Farm to Market roads in the Iowa secondary road system. The Local Secondary system carried a traffic load of 2,714,180 daily vehicle miles, accounting for 32% of all traffic in the secondary system. For all Local Secondary roads having some form of surfacing, 98% were surfaced with gravel or crushed stone. During the 1970 construction year 335 miles of surfaced roads were constructed in the Local Secondary system with 78% being surfaced with gravel or crushed stone. The total maintenance expenditure for all secondary roads in Iowa during 1970 amounted to $40,086,091. Of this, 42%, or $17,020,332, was spent for aggregate replacement on existing gravel or crushed stone roads with an additional 31% ($12,604,456) being spent on maintenance other than resurfacing. This amounts to 73% of the total maintenance budget and are the largest two maintenance expenditure items out of a list of 10 ranging from bridges to drainage assessments. The next largest item was 7%, for maintenance of existing flexible bases. Three concurrent phases of study were included in this project: (1) laboratory screenings studies of various additives thought to have potential for long-lasting dust palliation, soil additive strength, durability, and additive retention potential; (2) test road construction using those additives that indicated promise for performance-serviceability usage; and (3) observations and tests of constructed sections for evaluation of the additive's contribution to performance and serviceability as well as the relationship to initial costs.

Surface Improvement and Dust Palliation of Unpaved Secondary Roads and Streets, Progress Report, HR-151, 1971

A combined study of dust control and low-cost surface improvements of soil and aggregate materials for immediate (and intermediate) use as a treated surface course is being conducted in three concurrent phases: (1) laboratory screening of various additives thought to have potential for long-lasting dust palliation, soil-additive strength, durability, and additive retention potential; (2) test road construction, using those additives from the screening studies that indicate promise for performance and serviceability; and (3) observation and tests of constructed sections for evaluation of the additive's contribution to performance and serviceability as well as relationship to initial costs. A brief review is presented of the problem, some methods of measuring it, previously adopted approaches to it, project field tests and a portion of the results thus far, and portions of the laboratory work accomplished in the screening studies.

Criteria for the Evaluation and Disposition of Low-Traffic-Count Secondary Roads, HR-139, 1969

The State of Iowa has too many roads. Although ranking thirty-fourth in population, twenty-fifth in area, and twentieth in motor vehicle registration, it ranks seventh in the nation in miles of rural roads. In 1920 when Iowa's rural population was 1,528,000, there were 97,440 miles of secondary roads. In 1960 with rural population down 56 percent to 662,000, there were 91,000 miles of secondary roads--a 7 percent decrease. The question has been asked: "Who are these 'service roads' serving?" This excess mileage tends to dissipate road funds at a critical time of increasing public demand for better and safer roads.

Guidelines for Removal of Traffic Control Devices in Rural Areas, TR-527, 2005

It is commonly regarded that the overuse of traffic control devices desensitizes drivers and leads to disrespect, especially for low-volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer’s (ITE) Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approach(es) to stop is left to engineering judgment and is usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume itself is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer (or perhaps never) met engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop-controlled intersections. The scope of this research is ultra-low-volume (< 150 daily entering vehicles) unpaved intersections in rural agricultural areas of Iowa, where each of the 99 counties may have as many as 300 or more STOP sign pairs. Overall safety performance is examined as a function of a county excessive use factor, developed specifically for this study and based on various volume ranges and terrain as a proxy for sight distance. Four conclusions are supported: (1) there is no statistical difference in the safety performance of ultra-low-volume stop-controlled and uncontrolled intersections for all drivers or for younger and older drivers (although interestingly, older drivers are underrepresented at both types of intersections); (2) compliance with stop control (as indicated by crash performance) does not appear to be affected by the use or excessive use of STOP signs, even when adjusted for volume and a sight distance proxy; (3) crash performance does not appear to be improved by the liberal use of stop control; (4) safety performance of uncontrolled intersections appears to decline relative to stop-controlled intersections above about 150 daily entering vehicles. Subject to adequate sight distance, traffic professionals may wish to consider removal of control below this threshold. The report concludes with a section on methods and legal considerations for safe removal of stop control.

Report on the Iowa Judicial Retirement System as of June 30, 2015 and the net pension liability as of June 30, 2014

Report on the Iowa Judicial Retirement System as of June 30, 2015 and the net pension liability as of June 30, 2014