Figure 30: The grouping of PennDOT regional offices with similar climate conditions. PennDOT, 2021

Figure 30: The grouping of PennDOT regional offices with similar climate conditions. (PennDOT, 2021)

6.1.2 Case 2: Changing Construction Month

Case 2 shows the effect of changing the construction month, in this case from May to October. On average, October is a colder month than May which can significantly slow the heat of hydration in concrete, reducing the rate of strength gain. In this simulation, cracking and dowel bar performance reliability and ESAL repetitions are 95.7%, 59.8%, and 1419, respectively. There is a significant difference for each of these values when compared to the same pavement constructed in May. The cracking performance increases accounting for the increase in stiffness due to the colder weather while the dowel bar performance reliability decreases and ESAL repetitions increase to account for the slow rate of strength gain.

6.1.3 Case 3: Changing Traffic Pattern

Case 3 shows the effect of changing the traffic pattern, in this case from Minor Arterial to Residential. This input controls the amount and size of vehicles traveling on the pavement. A decrease in traffic of 415 ESALs is caused by the user changing the traffic pattern from Minor Arterial to Residential. In this simulation, cracking and dowel bar performance reliability are 99.1% and 99.9%, respectively. The large increase from the original example shows that allowing lighter weight traffic early is beneficial to lower congestion while maintaining pavement performance reliability. Changing the allowable traffic to achieve this reliability is a viable method for reducing the user cost of any road type including interstates and minor arterials.

6.1.4 Case 4: Changing PCC Thickness

Case 4 shows the effect of changing the PCC thickness. In this case PCC thickness was increased from 6 to 9 inches. Since the PCC is thicker and therefore stronger, the cracking performance reliability and dowel performance reliability are 100% and 99.7%, respectively. This case also sees a higher number of ESALs (1021) before design strength is reached.

Table 8 shows a comparison of each case.

Table 8: Example cases varying location, construction month, traffic pattern, and PCC thickness.

Example Case 1 Case 2 Case 3 Case 4

Location Region 2 Region 4 Region 2 Region 2 Region 2 Construction Month May May October May May Traffic Pattern Minor Arterial Minor Arterial Minor Arterial Residential Minor Arterial PCC Thickness 6 in 6 in 6 in 6 in 9 in Cracking Reliability 88.7% 89% 95.7% 99.1% 100% Dowel Bar Reliability 77.5% 74.6% 59.8% 99.9% 99.7% ESALs to design strength 997.7 1058 1419 415 1021

7 Analysis of Work-Zone User Delay Costs

In the recent years, considering that the National Highway System is essentially complete, the focus of road construction has switched from building new roads to reconstructing and renovating existing infrastructure. Still, most of the existing roadways are beyond their useful design life. Consequently, work zones resulting from the need to address the reconstruction projects bring significant impacts on mobility, safety, and economic productivity of the relevant region and stakeholders. From partial to full road closures, the severity of work zone impacts could vary significantly. Depending on the type of the work zones, these impacts consist of growth in traffic volumes, congestion, increased travel time, and a reduction in safety, reliability, mobility, and economy in the area. These factors heighten the need for finding innovative and efficient ways to assess and improve mobility and safety in the paving industry work zones.

This is a potential area for the early opening procedure described in this project to benefit construction practices. Saving a relatively small amount of time on a long, new construction project is not useful because curing time is not a stationary time. The construction can continue to other areas on the construction project. However, small repair projects, especially in urban areas, can benefit greatly from any construction time shortage possible to reduce traffic and congestion. Arterial roadways farther benefit because work zones do not only affect the roadway being repaired, but congestion can spread to the surrounding network of roads. The bus network is also highly affected by arterial work zones and farther affect the transportation efficiency of the city.

According to the Federal Highway Administration (FHWA) Office of Operations, congestion derives from several factors which can be split into six root causes, often interacting with one another (FHWA, 2020). Figure 31 depicts an estimation of how much each of these sources contributes to the total congestion. As a matter of fact, not only work zone by itself stands for 10% of the total congestion, but also, it is one of the main reasons for bottlenecks' occurrence (FHWA, 2020). Therefore, transportation agencies across the country are trying to make travel through and around work zones safer and more efficient, especially in terms of travel time and delay.