When I was growing up in Scotland, my grandmother would pass knowledge on to me in the form of proverbs. When I’m waiting at a red traffic signal I remember one of her many sayings “If it’s fur ye, it’ll nae gae past ye”, roughly translated as “if it’s for you, it won’t go past you.” No need to worry, you’re green time will come. At traffic signals everybody loves a green light because it means “go”. I believe that for the entire smart roadways movement, green should mean go, too. There is an important focus on being green. From a transport point of view, this means careful management of the unwanted side effects of the transport process, while maximizing the good things that we desire – safety, efficiency, and great customer experience. It is a challenge to go for green while also attaining the other goals. It’s not easy, but it is absolutely possible with the right approach.
“Road transport constitutes the highest proportion of overall transport emissions (in 2019 it emitted 72% of all domestic and international transport GhG).” 
What it means to be green
First, let’s define what it means to be green from a roadway point of view. The figure below captures the process that we need to follow. We can be greener by understanding challenges, developing appropriate responses, and implementing solutions that support responses.
Green has particular relevance for urban traffic signal control as every driver likes green traffic lights to keep going. More important is the ability to manage journeys through the road network in a way that optimizes traffic flow as it varies over the course of the day. Ideally, advanced traffic management will exactly align the green signal time with the traffic flow on each approach.
Greenness for roadways
Let’s discuss an ideal, one-way journey as depicted in the figure below.
The pink line represents the planned or ideal journey, the red represents the actual journey. The nodes represent stage points in the journey. They could be timing points for a transit service, or modal interchanges for a traveler. They might also be major intersections along a limited access highway. For example, at point 2, the traveler might switch from local bus to commuter rail. You can see that at point 1, the journey is taking longer than planned. Time is made up between points 1 and 2, but lost again between points 3, 4 and 5.
There are two points that I would like to make here:
- First, the planned or ideal journey must be optimized for greenness: minimum carbon footprint, fuel consumption, and other factors that affect greenness. These include choosing the best mode of transport for the prevailing condition, matching the journey’s purpose. It also includes managing those modes as effectively as possible, adapting to changes in the demand for transport and prevailing operating conditions. It is also essential to inform travelers about the choices they have for any journey, for any purpose, and at any time. These might be pre-planned, scheduled journeys, or spontaneous travel decisions. Mobility as a Service techniques can be used to inform the traveler, help them make a single reservation across the entire journey from origin to destination and support a single, convenient electronic payment for the travel services to be used.
- The second point is that any deviation from the ideal or planned journey can be viewed as a “loss of greenness.” In this case, the cumulative journey time increase (the red areas) could be caused by congestion or delay, reducing the journey greenness. This comparison of an ideal to actual journey is a technique used in aviation but typically not in surface transportation. In order to attain green, it will be necessary to have sufficient data collection and analytics capability to plan the optimum journey and monitor deviation from ideal during the actual journey. It will also be necessary to have the degree of situational awareness and management capability to improve the actual journey in formative, near real time ways. It is interesting to note that taking this approach to defining and measuring greenness also enables other factors to be optimized including safety, efficiency, user experience, and equity. Equity is improved by operating cost reductions making transport more accessible to all by reducing travel costs. We must go green and use management tools to stay green, for every stage of every journey.
This is complicated and yes, as I said at the start, it is not easy, but it is entirely doable. It can be done by applying information and operational technologies such as those depicted in the figure below.
The operational technology is the part of the iceberg under water, unseen but irreplaceable. Information technology consists of various elements above the water, which deliver visible impacts but rely on the unseen operational technology. Together they support the range of customer facing applications that deliver greenness. Like the iceberg, I am focusing on just the tip of the greenness issue.
Technology can enable us to determine carbon impacts for different stages in the journey and all modes of transport. We can even look at the supply chains that deliver transport infrastructure and vehicles, ensuring that we optimize the bigger picture supporting circular economic approaches. Smart roadways and intersections are crucial elements in this due to the proportional impact that effective operations have on greenness. We can not only make our roadways greener, but also the entire transport system. From better intersection management to world-class high-speed highway operations, we have the tools available now to go green.
Green is for now
So why is it important for roadways to be greener now? We want to save the planet and reduce greenhouse gases (GhG)—bold political goals have been set. Transport contributes a significant amount of GhG, especially road transport, so even a relatively small improvement would be significant. If we are to achieve these bold goals within the required time, then it’s time to start planning and implementing. There are proven technology solutions that can be implemented off the shelf including advanced traffic management, electric cars and trucks, AI based decision support and advanced sensors. Robust, trusted OT networks can underpin the attainment of bold goals.
Grandma’s guide to greenness
In addition to her many sayings, my Grandmother would also give me sage advice. One piece of her advice was that to get what you want, there are two fundamental steps required. Step one is to decide what it is you want. Step two is to ask for it. We have obviously decided that we want greener roadways and transport. So now we have to ask for it by designing, specifying, and procuring it. It’s still not easy being green, but it is now easier than ever due to bold political action and capable technologies. Let’s go for green.
Want to know more about smarter, greener, and safer roadways? Click here!
Visit our booth #1246 at ITS World Congress on September 18-22, 2022. Cisco will also participate in the session STS2: Truck safety – a total perspective from data to action.
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 Greenhouse gas emissions from transport in Europe, European Environmental Agency, November 2021