To investigate the traffic conflict characteristics in tunnel-interchange optimal segments, the study employed unmanned aerial vehicles to capture and extract real vehicle trajectory data from three representative locations. Based on observations of traffic flow conditions, the study categorized typical types of traffic conflicts and assessed their severity using Time-to-Collision (TTC). And then revealed the distribution characteristics of traffic conflicts in these restricted segments. To establish the relationship between the traffic conflict rate in these segments and road geometry and traffic flow factors, a multiple linear regression model was employed. Significant influencing factors were identified, and their impacts were quantified. The results indicate that the most concentrated conflicts occur during lane changing and rearend situations in the middle lane. The primary area for severe conflicts spans from the tunnel exit to the end of the taper section in the longitudinal direction. Additionally, as lanes shift outward and spacing decreases, the concentrated area of lane-changing conflicts gradually approaches the taper section from the tunnel exit. The length of spacing, average speed difference, traffic volume, diversion ratio, standard deviation of overall speed, and standard deviation of lane-changing speed significantly affect the traffic conflict rate in tunnel-interchange optimal segments, with their influence decreasing in order.
The rate of traffic accident is typically very high in tunnels due to the relatively closed environment, small space and poor internal light, particularly in mountainous areas that the pavement in long tunnels. Normal asphalt concrete pavement performs poorly in terms of resisting both fire and water damage. There is a strong need to propose a novel asphalt concrete for tunnel paving to achieve better fire resistance and long-lasting pavement. A new fire-resistant epoxy asphalt material containing a low resin content of 6-11% was developed in this study. Consequently, a novel post-doped construction technology is proposed to meet the harsh requirement of construction timing of epoxy asphalt. The properties of the epoxy asphalt concrete under different temperature conditions were evaluated for water stability, kerosene immersion, and fire resistance test, as well as accelerated loading test in water at temperature of 60℃. The epoxy asphalt was successfully used to construct a 3cm-thick pavement by the post-doped constructing method in a highway tunnel in Yunnan province, China. The results of this study provide an alternative asphalt concrete mixture and construction method for tunnel paving with the features of fire-resistant and long-lasting.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.