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Roadwork zones represent a hazardous place within the highway system, with higher crash rates and injury severity, often due to excessive speed and noncompliance with speed limits. On freeways, a common layout is to close a full roadway and to divert traffic onto the opposite roadway, with one lane closed to accommodate the redirected traffic, by driving through the median strip. In this scenario, the second chicane can be a hazardous point if it is not correctly signaled. This paper examines the need to install a speed monitoring display (SMD) before the returning chicane on a bypass. A two-phase study was conducted on a Spanish freeway where a roadway was temporarily closed. Two measurement points were established on the bypass, one in the middle and one at the end, prior to the return chicane through the median strip. During Phase 1, the portable SMD was installed and during Phase 2, it was removed. The average and the 85th percentile of the speed distribution at each point during both phases were compared. Additionally, mean difference tests were conducted and a speed prediction model was developed. With the SMD, drivers reduced their speed from the midpoint to the returning chicane, within the range of 7-10 km/h. Conversely, upon removal of the SMD, motorists increased their speed while driving through the bypass, resulting in excessive speed at the most hazardous point, the chicane leading back to the original roadway. The difference in mean speed between the two phases was 18 km/h at the returning chicane. In addition to the traffic calming measures implemented prior to entering roadwork zones on freeways, which are conveniently established in the standards; it is necessary to evaluate potentially dangerous areas of the layout and implement additional measures where required. Specifically, in the case of final chicanes of bypasses with reduced radii, it is recommended that a speed monitoring display be installed as a mandatory element in order to inform drivers of this challenging segment. Highway administrations around the world should maintain a SMD at the returning chicane of a bypass while roadworks last. [ABSTRACT FROM AUTHOR] more...

Probabilistic pavement models, with Markov chains as the most widely used type, are considered to capture an accurate representation of the in situ pavement performance. Homogeneous Markov chain models present the same transition probability matrix (TPM) for all the transitions of the period and require data from multiple duty cycles of one or two years. The aim of this paper is to explore the feasibility of developing homogeneous Markov chain models with variations of the duty cycle (in increments of either one or two years). Without considering maintenance and rehabilitation works, this research found that TPMs for a one-year duty cycle can be calculated from the two-year duty cycle, without a noticeable effect on accuracy using International Roughness Index (IRI) values from the Spanish State Road Network. However, for developing coherent TPMs, two primary assumptions were made: (1) heavy vehicle traffic volumes determine the traffic category (TC), and (2) only roads from the same climatic region were modelled. The satisfactory results verified the validity of the methodology and overcame the disadvantages of homogeneous Markov models. Furthermore, the results suggest that pavement sections are adequately designed in Spain for each TC because of the similar deterioration patterns. [ABSTRACT FROM AUTHOR] more...

The available skid resistance, or friction, in a pavement surface is a vital parameter for functional evaluations of roads due to its relation with crashes. Therefore, highway administrations must collect friction data on their road network to provide safe roads to users. Additionally, a prediction model that can forecast the available skid resistance in each road segment is necessary for an efficient pavement management system (PMS). The aim of this paper is to develop a skid resistance prediction model for the bituminous pavements of the motorway network of federal state of Bavaria, in Germany, with information that is typically available in a PMS: the Annual Average Daily Traffic , the Annual Average Daily Heavy Traffic , and the number of lanes in each segment. Despite its simplicity, with 6410 road segments of 2 and 3 lanes of the Bavarian motorway network, the model achieves a determination coefficient (R2) of 0.405. If information about the surface layer material is added, R2 increases to 0.480. Consequently, apart from predicting the minimum available friction in each lane in a motorway, the study underlines the necessity that a PMS should contain the recommended elements and additional surface layer material, because the quality of the prediction improves. [ABSTRACT FROM AUTHOR] more...

Pavement management systems employ pavement performance models to plan the most effective allocation of public funds. The most used models are the deterministic and the probabilistic or stochastic ones. Among stochastic models, the Markov Chains are receiving considerable research attention. In this paper, transition probability matrices (TPMs) are presented for Portland Cement Concrete (PCC) pavement road network in the Republic of Moldova with available International Roughness Index (IRI) data collected in spring and in autumn from 2013 to 2015. Although one-year cycle time is usually employed, half-year cycle time was defined to handle a bigger amount of transitions. The aim of this paper is to prove that TPMs for rigid pavements can be developed using IRI values from a short period, with a half-year step time, for a road network where the time since last major rehabilitation varies in each section and where maintenance and rehabilitation activities are carried out simultaneously. In order to consider all these aspects, some assumptions must be made. Roughness seasonal variations can arise in PCC pavements due to the effect of curl and warp. Hence, a threshold of 0.40 m/km was defined as the maximum improvement on a section after half-year step for not being considered as maintenance work or spurious data. When the IRI value improves more than 4 m/km after one step, a rehabilitation activity is considered. That rehabilitation is not used in the matrix calculation, but the subsequent deterioration contributes. Results demonstrate that rigid road sections can jump two condition states in one transition, instead of only remaining in the same condition state or shifting to the next one. Obtained matrices give an overview of deterioration tendencies of rigid pavements, and they fit better to real data if a large proportion of no rehabilitated or maintained sections are compared to predicted values. [ABSTRACT FROM AUTHOR] more...