The fatigue failure probability of the bridge at two selected locations under the long-term effect of highway traffic is calculated for a 100 year-design life.
The instantaneous network traffic is the sum of flow rate within per unit time, and the average traffic is calculated by the following formula: {mathrm{ANT}}_i=frac{sum limits_{j=1}^i{nt}_j}{i} (27).
For each link e= u,v), its carried traffic is calculated as (f^ u,v =sum ^{C}_{i=1}{sum ^{K}_{j=1}{f^ u,v,i,j }}). Here, we are only interested in the volume of traffic on a link between two nodes for routing purpose regardless of which channel it operates on and how many MIMO streams are used.
For the whole length of the highway, the commercial traffic was calculated to be 246 trucks daily in 2009.
IRRs for the two traffic proxies (major road and traffic load) were calculated using enrollment addresses.
Incidence rate ratios (IRRs) for diabetes in association with road traffic noise were calculated for a) average yearly road traffic noise at the current residence, and b) time-weighted mean road traffic noise during the previous 5 years.
Exposure differences and percent differences between high-traffic and low-traffic rides were calculated for each subject.
Traffic densities were calculated within buffers covering different perpendicular distances from roads, using the kernel density plotting for line features of the Spatial Analyst extension in ArcInfoGIS9.1 (ESRI, Redlands, CA).
Traffic densities were calculated on a 20 × 20 m grid using the kernel density plotting feature of Spatial Analyst in ArcInfo GIS 9.1 (ESRI), which effectively caused the densities to decrease from volume-dependent values at roadway edges to zero at 500-m perpendicular distance from roadways.
Because all traffic-related exposures were calculated independently from health outcomes and potential confounders, systematic error is unlikely, and random error would probably dilute associations between exposure and outcome.
