Urban traffic at a standstill

Congestion has increased significantly. A trend that is set to continue. Here are four examples of DTU-projects aimed at relieving traffic congestion.

Economic growth, higher employment, increased consumer spending, and a growing number of vehicles are key reasons why congestion on Danish roads has increased significantly since 2010. And this is set to continue: A projection for 2030 shows 16 per cent overall growth in Danish personal vehicle traffic compared to 2015. Road freight transport is expected to grow by approx. 12 per cent. The world needs smart solutions that can get traffic moving.

Read about some of DTU’s projects which can help relieve the congestion.

Shorter waiting time at the bus stop

Hunting for parking spaces adds to congestion

City Logistics: More products delivered to cities

Can autonomous buses provide the last link in the chain?

Shorter waiting time at the bus stop


Traffic researchers have developed algorithms that optimize timetables and reduce waiting times for public transport.

DTU researchers have developed algorithms that can optimize public transport timetables and reduce waiting times at stops.

Short waiting times are an important factor in how people perceive public transport, according to Evelien van der Hurk, a researcher at DTU Management.

“We know that passengers experience waiting time as three times longer than if they spend the same time in the bus or train. So it will improve how people experience public transport if waiting time, in particular, can be minimized,” says Evelien van der Hurk. She notes that it is vital for public transport to be perceived as an attractive solution if society wishes to prevent more and more people choosing to drive. More automobiles will mean more pollution and more congestion on roads:

“Public transport has to be part of society’s transport solutions. We need to travel in groups if we want to have a sustainable future and cities that are pleasant to live in.”

Bus timetables have special potential

Bus timetables, in particular, hold potential that could benefit passengers, the researcher notes:

“Bus routes are not as fixed as train, metro, and light rail traffic, which has to follow the tracks. Busses also carry fewer passengers at a time, so their routes can be more easily adapted to where passengers need to get on and off,” says Evelien van der Hurk.

Assistant Professor Evelien van der Hurk and her colleagues have shown that it is possible to reduce waiting time using mathematical optimization.

Assistant Professor Evelien van der Hurk and her colleagues have shown that it is possible to reduce waiting time using mathematical optimization.

The algorithms have been developed as part of the Integrated Public Transport Optimization and Planning (IPTOP) project, one of the partners in which is Movia. Movia is represented by Timetable Manager Poul Bayer, who is familiar with the challenges of optimization and minimizing waiting time.

“Optimizing timetables is a complex task, where waiting time is one of the factors. It can no doubt be supported by tools that help the planner make the right choices,” says Poul Bayer.

Finding the best solution

The optimization is being done using operational analysis (see fact box) which requires calculations, analyses, and mathematical models, and large amounts of data on passenger numbers, trip lengths, routes etc.

“Optimization means finding the best solution. But first you have to define what you mean by the ‘best solution’. There is also a budget that has to be met. How much money can you spend? This has both political and user-related elements, which mathematics cannot address,” explains Evelien van der Hurk.

She also notes that the time it takes to find the optimal timetables is an important factor:

“It’s important that the algorithms help to find the solutions quickly. It’s not much use to have an optimal timetable in ten years’ time, if it is based on data on the needs and travel habits of passengers in 2019.”

Dynamic timetables

The algorithms the DTU researchers have developed for timetable optimization can work out a good timetable in just a few hours. This process normally takes weeks or even months. Fast algorithms also make it possible to create dynamic timetables, so that public transport adapts more flexibly to the needs of passengers, special events, and variations in the seasons and weather conditions.

Movia’s timetable manager looks forward to implementing the researchers’ work.

“The results we have seen presented so far look very interesting. We look forward to using the results in an operational form, so that we can benefit from them in our planning and translate our knowledge into better service for customers,” says Poul Bayer.

Hunting for parking spaces adds to congestion


Drivers searching for parking take up space on city roads. In Copenhagen, the EasyParks app can guide you to the nearest parking space. DTU has provided advanced algorithms and statistical analysis.

A part of the congestion on city streets is due to cars driving around searching for a parking space. This congestion can be reduced if drivers find a parking space more quickly.

In early 2018, Easypark launched a new function in their parking app for phones that helps drivers find parking in Copenhagen. The Find & Park function shows drivers where they are most likely to find a vacant parking space close to their final destination.

The new Find & Park function came about with the assistance of researchers at DTU Compute, who developed algorithms and statistical analyses based on a huge data set with many sources.

“We helped EasyPark combine the various parking data sources. We used information on resident licences, business licences, paid parking and specific traffic measurements. The challenge has been to combine the very large and diverse volume of data and build a model that can suggest where vacant parking spaces might be found with very high precision,” says Professor Bjarne Kjær Ersbøll from DTU Compute.

Colour codes guide the driver

EasyPark is very satisfied with the result.

“In cooperation with the researchers, we have been able to complete a comprehensive research and data analysis project on parking behaviour and patterns in high traffic urban areas. This has led to the development of a range of innovative services for the benefit of motorists and urban environments alike,” says Maurus Haefliger, product owner and business developer at EasyPark Group.

The Find & Park function displays a map of the urban area where the user wishes to park. Each street is presented with a colour code for the given time of day when the user is looking for a parking space. A red street means less than one free parking space per 100 metres, orange indicates one or two spaces, and green means at least two parking spaces per 100 metres. The app is based on probabilities, so there is no guarantee that the driver will find a parking space. But is does provide an estimate of the time the user can expect to spend finding a parking space.

Colour codes guide the driver to the streets where there is the greatest chance of finding a vacant parking space.

Colour codes guide the driver to the streets where there is the greatest chance of finding a vacant parking space.

Finds parking spaces in half the time

In 2017, an early test of the Find & Park function in Stockholm found that motorists halved the time they spend looking for parking.

“This saves valuable time for drivers and avoids stress, while also reducing traffic and pollution in cities, making them greener and easier to get around in for everyone,” says Maurus Haefliger.

The function has so far been rolled out in Copenhagen and Rotterdam, but EasyPark expects several more cities in Denmark and abroad to be added.

More products delivered to cities

Cities are growing, and we are shopping more on the Internet. These two trends mean that more items have to be delivered to cities, putting strain on the road system.

Boots, skimmed milk, skateboards, and many other items are being added to ‘shopping baskets’ in Danish homes as we shop on the Internet. Each time we complete a transaction in a webshop, we set a parcel delivery in motion. Somewhere in the country, a truck makes the journey from a warehouse to our front door—or the nearest parcel pick-up location.

It is now a common sight in urban areas for multiple delivery vehicles to drive to the same street on a given day. First UPS, then GLS, DHL, PostNord, and several others. In other cities you also see businesses like nemlig.com drive out to residential areas—perhaps several times a day, depending on what time the various households have requested delivery of their groceries. From a transport researcher’s point of view it makes no sense:

“We have a high number of parallel transport systems for delivering goods. From an optimization perspective, this is ridiculous. But there is demand and a market for the quick delivery of goods—overnight, or even down to within the hour—and consumers have become accustomed to being able to get goods delivered whenever it suits them,” says Allan Larsen Professor at DTU Management.

Road freight transport is expected to grow by approx. 12 per cent, according to the ‘Mobility for the future’ expert group in 2018.

Road freight transport is expected to grow by approx. 12 per cent, according to the ‘Mobility for the future’ expert group in 2018.

E-commerce increasing congestion

E-commerce is one of the trends we will increasingly notice on the roads, because it contributes to more trucks on the asphalt. About 15 per cent of vehicles in cities and towns are vans and trucks.

The ‘Mobility for the future’ report, prepared by an expert group for the Danish Ministry for Transport, Building, and Housing in 2018, concludes that “freight traffic can be expected to grow as a result of the continued rise in e-commerce”.

The report also notes that the increasing volume of e-commerce offers opportunities for optimizing and consolidating distribution, so the effect on traffic is reduced. In this context, consolidation means packing the delivery vans carefully, so they do not drive around half-empty,” explains Allan Larsen. He has done research on Urban Consolidation Centres (UCCs)—collection centres outside cities where goods are delivered and repackaged, before being driven into towns in full trucks and vans along optimally planned routes. The idea sounds brilliant, but ...

“Some believe that better consolidation can solve all challenges posed by the increasing number of deliveries in urban areas. Unfortunately, it’s not quite that simple,” says Allan Larsen.

“Many of the vans and trucks that drive into cities and towns are already fully consolidated. The large chains, in particular, are good at exploiting truck capacity. There are also trucks carrying cold and frozen goods which are not suitable for repacking at a collection centre, as there is a risk of breaking the cold chain which could affect food safety.”

Empty vehicles on return trip

The professor estimates that once the fully consolidated vans and trucks and cold and frozen transportation are removed, only a few per cent of the total number of vehicles on the road are vans and trucks which could be better consolidated.

“The limited number of vans and trucks you can remove by using Urban Consolidation Centres will unfortunately not solve congestion problems alone. But that doesn’t mean this option should not be exploited. We just need to look at more solutions at the same time if we hope to reduce congestion caused by goods traffic,” says Allan Larsen.

However, there is untapped potential for consolidation, when the trucks leave the cities and towns again, Allan Larsen believes:

“Once the goods have been unloaded, most vehicles leave the city again empty, and you could better utilize them by carrying cardboard or other waste out again, for example.”

Consolidation thus has a limited potential to reduce the congestion according to the professor, who does not see drones or wheeled robots as major solutions either. He believes these are unrealistic, impractical, and not something that would make cities more pleasant to live in.

“Imagine the noise in urban areas if drones took over deliveries. I don’t think city residents would like that. The number of items that can be delivered by drones is also limited, as they are best suited to carrying relatively light packages. We also need to remember that energy consumption for air transport is much higher than for ground transport. Again, I’m not saying that we should not look at drones at all, but that they will only be a very small part of the solution,” says Allan Larsen. He also shakes his head at the idea of small wheeled robots delivering packages to city residents.

“They could perhaps form part of some delivery solutions, but we can’t have the pavement in front of an entrance blocked by 20 robots waiting for the residents to come home.”

Freight transport accounts for 30-50 per cent of the transport-related pollution in cities, Professor Allan Larsen reports.

Freight transport accounts for 30-50 per cent of the transport-related pollution in cities, Professor Allan Larsen reports.

There is no one quick fix

‘Mobile hubs’ could perhaps be trialled instead. These are a kind of mobile package collection site where residents can pick up their deliveries.

“A container is filled with packages outside the city and brought in. This solution is being tested right now as a demonstration project in Hamburg,” says Allan Larsen.

In other words, the professor believes there is no one quick fix that will ease congestion as more and more goods have to enter towns and cities.

“It’s important to bring all solutions into play, but also to invent and test new concepts such as mobile hubs. In relation to e-commerce, we can also discuss as a society whether it should only be the market that decides how often a delivery vehicle drives into the city. Perhaps the boots from Zalando can wait a few days before being delivered. So that they can arrive together with other packages for your street. But such a solution may involve some unpopular choices, as it requires that politicians dare to introduce some form of regulation of consumer behaviour.”

Can autonomous buses provide the last link in the chain?

Three self-driving buses are to be tested on DTU Lyngby Campus They are part of a project investigating whether autonomous buses can ferry passengers to and from public transport.

The distance to the nearest bus stop or station is a determining factor in whether or not people choose public transport. If it is too far to walk or cycle, the car’s heated seat and cup holder become more attractive, and public transport is rejected.

This challenge is referred to as the first and last mile problem: The first mile is how we reach the public transport system, and the last mile is how we get from public transport to our final destination. It may be possible for small self-driving buses to be used to fill these short transport gaps. The comprehensive Linc project examine aims to investigate this, reports Jeppe Rich, Professor at DTU Management.

“Our vision for self-driving buses is for them to ferry people to and from the nearest bus stop or station, leading more people to leave their car at home and use public transport instead,” says Jeppe Rich, who is contributing knowledge of traffic planning and passenger behaviour to the project.

Congestion can be reduced

The Linc project will test three autonomous buses in two selected areas—first at DTU Lyngby Campus, and later in Albertslund.

The test areas are within one of Denmark’s largest urban development regions—Loop City—which covers the ten municipalities through which Copenhagen’s 28 kilometre light rail system will run from 2025.

Fast and easy access to the 29 light rail stations may encourage more people to choose to use the system.

This potential is of interest to Nobina, reports Søren Jacobsen, who is the project leader in the company. Nobina operates around 4,000 public transport buses in Scandinavia, and the company is taking part in Linc in order to identify whether self-driving technology can already be integrated as a transport solution in public transport.

“If self-driving buses encourage more people to choose public transport, and we thereby reduce road congestion, it will make it easier for our other buses to get around. This can in turn lead more people to choose public transport, perhaps setting off a positive spiral,” says Søren Jacobsen.

Professor Jeppe Rich is participating in the Linc project and will gather knowledge about the passengers’ use of the self-driving buses

Professor Jeppe Rich is participating in the Linc project and will gather knowledge about the passengers’ use of the self-driving buses

Trial to investigate behaviour

During the two six-month test periods in Lyngby and Albertslund, Linc partners will collect more knowledge about passenger behaviour. The DTU researchers will contribute timetable optimization, among other things, that takes into account varying demand for the bus. This will initially be done by directing the bus to stops at which there is expected to be demand at a given time.

“We will collect data from a number of test volunteers to identify how they see the waiting time for the self-driving bus. We will also collect knowledge on how to communicate with passengers, and longer term, how they might use an on-demand solution, where they can book a trip using their mobile phone,” says Jeppe Rich.

Tests in Stockholm

Whether autonomous buses become the future solution that brings people to and from public transport will depend on technology development, according to Jeppe Rich:

“If faster buses are developed that can take more passengers, self-driving buses could come to play a major role—not just in cities, but also in rural areas where people travel longer distances.”

Nobina is already testing self-driving buses for first and last mile connections in a suburb in Stockholm, and has begun seeing the first positive results.

“People are using the buses. We cannot yet offer the option for buses to be booked for a specific journey. They are currently running on a fixed route according to a set timetable. There is room for 12 passengers in each bus, and they carry 7 passengers on average. We see these results as positive,” says Søren Jacobsen.