Research Article
Random Parameter Negative Binomial Model of Signalized Intersections
Table 3
Marginal effect/(elasticity) of random parameters and fixed parameters negative binomial models.
| | Variable | Random parameters negative binomial model | Fixed parameters negative binomial model |
| | Length of left-turn exclusive lane on major roads (m) | −0.064 | −0.090 | | Left-turn exclusive lane on minor roads (yes 1, otherwise 0) | −3.995 | −4.271 | | Pedestrian crossing on minor roads (yes 1, otherwise 0) | −20.049 | −29.542 | | Existence of median barrier on major roads (yes 1, otherwise 0) | −5.962 | −8.939 | | Existence of median barrier on minor roads (yes 1, otherwise 0) | −10.538 | −13.378 | | Number of major road lanes | 1.414 | 2.215 | | Lane width of major roads (m) | −0.409 | −0.729 | | Logarithm of heavy vehicle volume turning left on major roads | (0.511) | (0.436) | | Logarithm of total traffic volume turning left on major roads | (0.323) | (0.377) | | Logarithm of total traffic volume turning right on minor roads | (0.669) | (0.396) | | Logarithm of total traffic volume driving straight on major roads | (0.271) | (0.260) | | Length of median barrier on major roads (m) | (0.657) | (0.156) | | Length of median barrier on minor roads (m) | (0.236) | (0.156) | | Existence of traffic island on major roads (yes 1, otherwise 0) | −5.041 | −8.449 |
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