Roadway design isn’t something you typically notice — unless it’s done poorly. Bad design, on the other hand, does more than just frustrate drivers. It can contribute to more traffic accidents, delay emergency response vehicles, increase maintenance and repair costs, and have a negative impact on the environment. Bad design also has the potential to expose state and local governments to litigation.
A transportation engineer should consider a number of factors before proposing a design. In this blog, I’ll explore the obvious, and not-so-obvious factors that transportation experts should take into account.
But first, let’s take a step back and look at the role of a roadway designer.
What Is a Roadway Designer?
A roadway designer is tasked with developing roadway improvements to our highways, intersections, and other traffic-related infrastructure in compliance with state and federal design standards. Roadway design falls under the broad category of civil engineering.
What Are the 5 Basics of Roadway Design?
1. Safety
The number one priority in any design is the safety of the traveling public. In addition to speed and topography, roadway designers should also consider other factors that will improve safety, like reflective markers and signs to help drivers navigate the road or improvements to drainage systems to prevent road surfaces from collecting water.
2. Speed
The design should allow drivers to travel at a proper speed for the highway type. For example, an interstate highway where the speed limit is 75 mph will be designed differently than a rural highway where the speed limit is 45 mph.
Expected driving speed will influence the following:
- The radius of turns for sight distance
- Lane widths
- The grade of an incline or decline
3. Topography
Here’s another fairly obvious one. The forms and features of the land should be taken into account when designing any roadway. Roadway engineers have to make strategic decisions about the best way to accommodate mountainous terrain or bodies of water while balancing additional considerations, like cost and impacts to environmental resources.
4. The Surrounding Community
Unfortunately, it wasn’t always commonplace for state and local governments to consider community concerns when planning roadways, especially when budgets were tight. The result is that many expressways were built through less affluent neighborhoods, disrupting communities of color and exposing them to a disproportional amount of air, water, and noise pollution.
A modern approach to roadway design should take the surrounding community into account. An engineering company with a special expertise in environmental health and safety can also minimize pollution through efforts like creating a vegetative barrier between the roadway and surrounding neighborhoods.
Benefits of Vegetative Barriers
Vegetative barriers can be surprisingly effective. According to recent studies, these barriers can accomplish quite a bit:
- Improve air quality
- Increase property values
- Reduce heat
- Control runoff
- Lower noise
However, just like most concepts in engineering, it’s all about balance and thorough planning. Adding roadside vegetation can also affect sight lines, narrow road shoulders, benefit invasive species, and pose an additional fire hazard in some environments.
5. Sustainability
Concrete is the second most widely used substance on the planet, right after water. Our interstate system is 60% concrete, which makes sense when you consider its ability to support heavy loads and go long periods without needing major repairs or resurfacing. But concrete has a few disadvantages that deserve consideration.
Drawbacks of Concrete
The environmental impact of concrete manufacturing and use is significant. Here are just the top few:
- Adds greenhouse gasses
- Damages topsoil
- Contributes to surface runoff
Concrete is also expensive, extremely heavy, it cracks easily, and it’s difficult to reuse. It can also contain soluble salts which may cause efflorescence — a chalky deposit that can form on the surface.
Scientists are currently working on some exciting alternatives to traditional cement manufacturing, and our team of engineers is looking forward to incorporating more of these materials into our roadway designs in the future.
Finding the Right Transportation Consulting and Engineering Firm
An environmentally-minded engineering firm has a greater focus on sustainability and community concerns when planning a roadway/transportation improvement project.
Here are a just few examples of how our team approaches roadway projects:
- Adding native plants to reduce erosion and minimize air, water, and noise pollution
- Looking for opportunities to repurpose existing materials
- Incorporating green technologies
- Taking advantage of our in-house geotechnical capabilities and specialized environmental teams to evaluate and mitigate potential risks
Clients often associate green design and construction with higher costs, but our roadway team has found that environmentally-friendly design is often no more expensive than traditional design as long as projects are well planned and incorporated early into the design process. .
In fact, as a full-service civil engineering firm, we’re able to save our clients quite a bit of time and money. Because of our depth of experience, we’re able to draw upon our internal resources to keep projects moving, from planning and compliance through completion.
Curious about what our team could bring to the table? Click below to learn more about how our team worked with the Pennsylvania Department of Transportation to address traffic congestion and safety concerns in Luzerne County.
Verdantas Communications
