Keywords : paired T
Engineering and Technology Journal,
2011, Volume 29, Issue 3, Pages 625-638
This paper was undertaken to investigate the relationships between speed
and density on urban arterial roads of Baghdad City. This research work was based
on the traffic survey data (PC volume and average speed) collected in Palestine
Street in 3 sections at two directions through 12 hours within 3 weekdays. The
density is computed using fundamental formula of traffic flow. Eight theoretical
Speed-Density models (5 are single Regime Models and 3 are Multi-Regime
models) are validated by the field data by two statistical test methods (CHISQ test
and Paired T-test). The results show that no one of the theoretical models is good
in fit with the real data. Then a Multi-Regime Model is improved under two ranges
of density (<70 and >70) at south approach and (<60 and >60) at north appraoch .
This model is tested using regression analysis, CHISQ test, and Paired T-test. This
analysis shows that the model has good fit with the field data.