Complete streets movement is a national effort to return to traditional streets in cities to enhance livability, safely, accommodate all modes of travel, provide travel choices, ease traffic congestion, and promote healthier communities. The California Department of Transportation (Caltrans) and several local agencies in the State have developed implementation plans for complete streets. In this project, the authors developed and tested improved strategies and analysis methodologies for complete streets, taking into consideration the emerging advances in technology on control devices and...
Trucking productivity can be significantly increased by moving freight with longer combination vehicles (LCVs). However, LCV operations not only raise safety concerns for the surrounding traffic and the LCV drivers themselves but also can damage roadways and bridges not equipped to support the operations. All the discussion about truck size and weight limitations or about the pros and cons of LCV operations is predicated on the use of conventional tractors and trailers. We however observed that a root cause of several major issues associated with LCV operations is the problem of off-...
Transportation Research Record: Journal of the Transportation Research Board
2021
The Highway Capacity Manual (HCM) employs a simple five-point system to assess the quality of bikeway pavement as part of the comprehensive bicycle level of service (LOS) evaluation. Unfortunately, the ambiguous and rudimentary nature of the existing HCM Pavement Quality Index (PQI) fails to offer an objective review of bikeways across different jurisdictions. In the following analysis, first is an assessment of the PQI and bicycle LOS in the HCM. To demonstrate the impact of the pavement quality rating and the importance of a more standardized evaluation method, a sensitivity analysis is...
This report presents data and analysis of a new mix type that has 100% replacement of aggregate and asphalt binder with reclaimed asphalt pavement (RAP) and the addition of a recycling agent. The data were collected from construction of a pilot project on Interstate 40 in San Bernardino County, which included the new mix , HyRAP® (a registered trademark owned by Brooks Construction Company, Inc. and licensed to Manhole Adjusting Inc. but produced under a non-proprietary Caltrans Non- Standard Special Provision), the control gap-graded rubberized hot mix asphalt (RHMA-G), and a dense-graded...
A research study was conducted with the goal of determining the expected performance life of thin bonded concrete overlay of asphalt (BCOA) in California. Eleven thin BCOA sections were built and tested with the Heavy Vehicle Simulators (HVS) in Davis, California. The performance of the sections in the HVS testing provided insight into the mechanics of the thin BCOA structures and the effects the different rapid-strength concrete materials, traffic, jointing, and base factors on their performance, including testing in both very wet and very dry conditions. Overall, the performance of the...
Internationally, full-scale accelerated pavement testing, either on test roads or linear/circular test tracks, has proven to be a valuable tool that fills the gap between models and laboratory tests and long-term experiments on in-service pavements. Accelerated pavement testing is used to improve understanding of pavement behavior.
The mechanistic-empirical design of concrete pavements traditionally assumes that concrete coefficient of thermal expansion (CTE) is a constant, however, experimental evidence shows that CTE can increase up to 60% as concrete dries. The research presented in this paper provides insight into the mechanisms that lie behind this phenomenon, by establishing a link between the diurnal variations of concrete internal relative humidity (RH) and the moisture-dependence of concrete CTE. The experimental data come from four concrete pavements, built with different high early strength mixes,...
The goal of the research presented in this report is to study how the mechanical properties of hot mix asphalt change upon the addition of high contents of reclaimed asphalt pavement (RAP) and the inclusion of any amount of recycled asphalt shingles (RAS), with between 25% and 50% binder replacement and to consider the addition of recycling agents to reduce the increase in stiffness and corresponding decrease in fatigue resistance. To achieve this goal, 16 mixes and the corresponding binders were fabricated and tested in the laboratory. The mix factorial includes a control gradation, two...
At the core of a mechanistic-empirical (M-E) pavement design method is a collection of performance models that each predicts the development of a specific pavement distress, such as fatigue cracking and surface rutting. Each model has both mechanistic and empirical parts. The empirical parts need to be calibrated to remove bias and increase prediction accuracy. This process has traditionally been conducted with small numbers of field sections for which materials may or may not have been sampled and tested. This paper presents a new calibration approach that uses network-level field data...
The in-situ asphalt stiffness master curve is a critical input for flexible pavement design. The master curve can be established directly by performing dynamic modulus testing on field cores, predicted using the volumetrics of the mixture, binder grade and aggregate gradation established using field cores, or backcalculated using falling weight deflectometer testing. There can be significant differences between the master curves established using these three different methods. The effects of these differences on design were compared using distress predicted by the asphalt pavement...
