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Insights What are the four major factors of roadway design?

The design of highways, streets and roads and the maintenance of these projects are highly important for vehicle safety and maneuverability. Quality roadway design directly impacts vehicle performance and driver comfort, and roads themselves are a key contributor to the development and growth of the economy.

Highway design primarily involves the layout and features visible on the road, gradients, intersections and the consideration of sight distance. Roadway and traffic engineers are trusted to ensure roadways are designed to the highest standard and are safe for drivers.

At AtkinsRéalis , and within our brands Atkins and Faithful+Gould, we help our clients meet their goals by delivering the best solutions to make communities safer. And it’s our expertise and capabilities that set us apart from the competition. By connecting people, data and technology, we deliver impactful roadway projects at scale across the USA. So what are the four major factors of roadway design?

highway set against a pink sky

The design speed

One of the most important factors affecting the geometric design of a road is the design speed—which is the speed at which drivers are intended to travel at while on the road. Several different variables contribute to design speed, and it’s also dependent on the person driving and the vehicle type—which is why design speed is an essential factor in roadway design. It’s critical that roadway engineers design roads that allow drivers to travel at the right speed. This includes developing narrow lane widths, tighter turning radius and other speed management techniques.


Topography in roadway design determines the arrangement of terrain, the different gradient increases and the construction cost. It also covers the physical location of the roadway and the surrounding areas, which may affect travel, such as lakes, rivers and even noise, and the overall stability of the location. Therefore, typography is a highly important factor in roadway design.

Traffic and people also affect the design of roadways. When developing a roadway, it’s important to consider the surrounding residents and the concerns they'll have around noise and air pollution. A commendable roadway design will be sustainable and built with a strong aesthetic that doesn’t affect the local environment.


The environmental aspects of roadway design can never be overlooked, particularly in the ongoing fight against climate change. With temperatures rising in the United States, engineers need to focus on sustainable roadway design. There are many different areas considered when designing an environmentally-friendly roadway, such as lower carbon materials, reduced emissions and waste, as well as using eco-friendly materials.

Concrete is a key contributor to greenhouse gases, and after water, it is the most used substance on the planet. The scale of impact this material has on our planet has inspired research into alternatives. According to research, a team of scientists from the University of Colorado Boulder, have developed an eco-friendly cement from Algae, which could dramatically reduce environmental pollution.


Designing for road safety is imperative for any engineer. There are many factors to consider to ensure drivers are safe on the roads, as well as techniques to improve the safety of roads. Improvement of minor and major junctions can be made using quality markings and signs to help drivers navigate the road. Every roadway should be built with illuminated raised pavement markings for facilitating safe travel during the night. When it comes to the physical design of a road, engineers need to consider creating appropriate bends to avoid interfering with a driver’s ability to see the road ahead. Also, civil engineers will need to install a drainage system to remove water from the surface of the road. Effective management of surface water is an essential part of the overall design and functioning of a roadway, and a major contributor to safety.

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