Glowing speed lines on a freeway diverging segment illustrate traffic flow.

Freeway Safety Reimagined: How Speed Consistency Can Save Lives

Jordan Keane in Tech & Innovation August 2025 • 4 min read.

"New research explores how consistent speeds on diverging freeway segments can reduce accidents and improve traffic flow."

For many, freeways are lifelines, rapidly connecting cities and enabling commerce. However, these high-speed arteries often face bottlenecks, especially at diverging segments where traffic exits the main flow. These areas are prone to frequent lane changes and abrupt decelerations, creating conditions ripe for accidents.

Understanding and mitigating these risks is crucial. Traditional approaches often focus on capacity and traffic flow, but a growing body of research highlights the importance of speed consistency. The more variable the speed, the higher the likelihood of crashes. This insight opens new avenues for enhancing freeway safety.

Recent research from Southeast University focuses specifically on evaluating the safety of diverging freeway segments based on speed consistency. By analyzing real-world speed data and applying innovative evaluation methods, this study offers practical strategies for making our freeways safer.

The Science of Speed Consistency: Why It Matters

Glowing speed lines on a freeway diverging segment illustrate traffic flow.

The core concept is simple: consistent speeds reduce the likelihood of accidents. When vehicles maintain similar speeds, there's less need for sudden braking or lane changes, both of which increase the risk of collisions. Diverging segments, by their nature, disrupt this consistency, as some vehicles slow to exit while others maintain highway speed.

Researchers at Southeast University leveraged a detailed analysis of traffic flow at a diverging segment on the G42 freeway in Nanjing, China. Using aerial video footage and advanced tracking technology, they collected precise speed data for individual vehicles. This data was then used to build a sophisticated model that predicts vehicle speeds based on factors like initial velocity and travel distance.

Data Collection: Aerial video footage was used to gather real-time speed data at three key cross-sections of the diverging segment.
Vehicle Classification: Vehicles were categorized into heavy and small vehicles to account for differences in driving behavior.
Speed Modeling: A linear regression model was developed to estimate vehicle speeds based on initial velocity and travel distance.
Safety Indicators: Average speed, speed difference, and the coefficient of variation were used to assess safety levels.

This model allows for a nuanced understanding of how speed variations impact safety. By identifying segments with high-speed variability, transportation authorities can implement targeted interventions to improve safety.

Practical Steps for a Safer Commute

This study offers valuable insights for transportation engineers and policymakers looking to improve freeway safety. By focusing on speed consistency and utilizing data-driven evaluation methods, we can create safer and more efficient roadways for everyone. The next time you're navigating a freeway exit, remember that maintaining a consistent speed not only makes your drive smoother but also contributes to the safety of everyone around you.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1051/matecconf/201712404007, Alternate LINK

Title: Speed-Consistency Based Safety Evaluation For Freeway Diverging Segments

Subject: General Medicine

Journal: MATEC Web of Conferences

Publisher: EDP Sciences

Authors: Ting Zhang, Qiaojun Xiang, Shen Li, Rao Yao, Yifan Guo

Published: 2017-01-01

Everything You Need To Know

What is the main concept discussed that can improve freeway safety?

The study suggests that understanding speed variations is key to safer roads. The research highlights the significance of speed consistency at diverging segments. The implications of this are that by focusing on speed consistency, transportation authorities can implement interventions to improve safety on the freeways. The diverging segments create disruptions due to the nature of the exits which leads to speed variations.

Why is speed consistency so important for freeway safety?

Speed consistency is crucial because it directly impacts the likelihood of accidents. When vehicles maintain similar speeds, there is less need for sudden braking or lane changes, which increases the risk of collisions. The study at Southeast University analyzed traffic flow on the G42 freeway. The model developed uses the average speed, speed difference, and the coefficient of variation to assess safety levels.

What are diverging freeway segments, and why are they a focus of this research?

Diverging freeway segments are specific areas where traffic exits the main flow, which creates conditions ripe for accidents. These segments often experience frequent lane changes and abrupt decelerations. The study at Southeast University focused on these segments. Understanding the speed variations at these segments is crucial for improving freeway safety and creating safer roadways for everyone.

How did the researchers gather and analyze the speed data?

Southeast University's study used real-world speed data from the G42 freeway in Nanjing, China, and analyzed it to assess safety levels at diverging freeway segments. Data collection included aerial video footage to gather real-time speed data. The study categorized vehicles into heavy and small, developed speed models, and used safety indicators like average speed and speed difference. These methods allow for a nuanced understanding of how speed variations impact safety.

What is the main idea to take away from this research?

The key takeaway is that maintaining a consistent speed contributes to the safety of everyone. The study offers practical strategies for transportation engineers and policymakers. By focusing on speed consistency, we can improve freeway safety. The research used data-driven evaluation methods to create safer and more efficient roadways. The interventions can include adjusting speed limits or modifying the physical layout of the diverging segments.