Roughness is the main feature of the pavement surface that defines user comfort. Pavement roughness is generally defined as irregularities in the pavement surface that adversely affect ride quality, specifically user perception of the road condition. This paper highlights the limitations associated with the evaluation and implementation of the international roughness index (IRI) on urban roads. The paper focuses on ( a) roughness evaluation with full-scale profilers and ( b) conditions particular to urban roads—namely, traffic, intersections, and operating speeds. Given that the speed of urban networks is typically less than the 80 km/h used in the IRI quarter-car model, the implementation of the IRI model on urban roads was evaluated. Even though a given pavement surface reported a unique IRI value, user experience of the profile depended on the travel speed. This result was evidence that user perceptions of road condition are highly influenced by travel speed. The results suggested the need to develop a roughness index that captures the unique characteristics of urban roads and can estimate the road condition as perceived by users. For that reason, this research study focused on establishing thresholds for IRI on the basis of the weighted vertical acceleration parameter as an aid to assessing user perception. The proposed method allows the maximum allowable IRI value for a given road to be established on the basis of the road’s operational speed. The results indicated that IRI thresholds agreed with international and local Colombian standards.

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The environmental impacts of natural aggregates (NA) and recycled concrete aggregates (RCA) production for use in road pavements have been evaluated in this study through an attributional life cycle assessment (LCA) from cradle to gate. Such effort is relevant considering the increasing interest of national agencies in applying recycled aggregates for construction and rehabilitation (C&R) of highway infrastructures. The study used site-specific data from two different aggregate production plants, stationary and mobile, both located in the northern region of Colombia. The stationary facility produces NA, and the mobile plant processes a combination of NA and RCA from the demolition of Portland cement concrete (PCC) pavements in the city of Barranquilla. The aggregates produced in the stationary facility are generally used as road base and subbase materials, and in the production of PCC, whereas the recycled mobile plant produces aggregate for subbase and road base mainly. Two scenarios were contemplated in the study. The first scenario involved extraction, hauling, and processing of NA. The second scenario involved aggregate (limestone) extraction, hauling, and recycling of RCA, and finally processing the combination of NA with RCA. The environmental impacts related to the production process of both stationary and mobile plants were evaluated using the computer program SimaPro 8.4.0 and the impact assessment method IMPACT 2002+. The results showed that diesel fuel is the principal energy used in both production processes, and is mainly responsible for the negative impact on respiratory inorganics, global warming, and nonrenewable energy. Results were very sensitive to transportation distances.