Future of Construction


A central platform to exchange best practices and ideas guiding the infrastructure and urban development industry in its transformation, and helping it to address its key challenges.

Transport in the Connected Age: Where technology could take us

The challenge

The age of the internet of cars is upon us and its impact will be felt everywhere. The autonomous car is an early example where we simply replace the driver with an AI. The case for a more fundamental transport revolution is now open – instead of cars competing with one other, how about cars collaborating with one another?

Today we have a situation where we compete against each other for road space. The result is congestion – the traffic jam. This congestion is perverse since what it does is reduce the capacity of the system dramatically. After all, if traffic is stationary the actual capacity of the road is zero.

The idea

So how can cars collaborate to improve this situation? In the end it has to be a negotiation about time slots on a road and how the limited resource can be optimized. Once the system is fully digital, all sorts of competing models are possible. One of the most prominent is some form of dynamic pricing which is exactly what is practiced in the airline industry – the price is adjusted to control demand so that the airplane is as full as possible. While some regard this as iniquitous, it does have the result of using the resource to maximum efficiency.


The determinants of capacity are two-fold – the average speed of the system multiplied by the average occupancy. The classic examples shown in textbooks are trains versus cars – a two-track train line has the same capacity as a six-lane freeway. The reason for this is human reaction times of car drivers – the safe reaction time on a freeway is normally regarded as twoseconds and this translates into a car separation of 200 feet. We often drive much closer, which works fine until there is even the slightest disturbance and we get congestion. Trains by contrast weigh hundreds of tons and are controlled by signals and safe separation.

What happens in the case of a digitally controlled car? We can now rely on the machine to drive us so reaction times are counted in milliseconds and we can use “platoon driving”, where cars drive only a few feet from each other. This technology has been explored for more than a decade by all the major car manufacturers, including trials to get cars from different makes to work together. This idea underlies the DSRC (Dedicated Short Range Communications) protocol already implemented in many cars.

Suddenly new options become available – cars when controlled collaboratively are highly efficient, in fact just as efficient as trains at the same speed. The analogy is with a sausage – either you have one with large lumps well spacedout – a train – or a sausage filled evenly all along – tightly spaced cars. Take a train and slice it so that you have four people, then take all the separations between trains and insert between the slices and you find a car will fit very comfortably in that space. As long as the system rolls cars are as efficient as trains. This points to having a primary network – like the freeway – and a secondary network – like ordinary roads to ensure an efficient network.

The barriers

But of course both trains and freeways rely on segregated tracks to achieve decent capacity – people aren’t allowed on train tracks, and nor freeways (motorways in the UK). In fact no system which co-exists directly with pedestrians can achieve high speeds, simple physics makes that inevitable.

Of course there is a line of argument which says sharing vehicles will change all of this. However, sharing vehicles ensures simply that vehicles are used more intensively (good in itself) but doesn’t actually change the number of trips taken in the system. The number of trips is the number of vehicles on the road and that seems likely only to grow, particularly as cities are relentlessly getting larger.

Over 3 billion people are likely to urbanize in the next 35 years, which is a formidable challenge.

If we now turn to urban mass transport, we see that on the whole as cities grow the only place we have to introdice new infrastructure is underground. Well-established cities like London and New York have done this for well over 100 years and it seems likely the same pattern will be followed elsewhere; certainly that is the current trend. Underground services already exist is cities, but there is plenty of space left deep down. The real problem lies in the 30 feet or so immediately below street level – that is highly congested.

Another key issue lies in the shape of any transport network. Cars and roads are popular because they are so flexible – take me from where I am to where I want to go without changing. Trains mostly mandate mode change – get to a station, wait for a train, change again and so on. It is made worse by the configuration of most urban mass transport systems – there are lines and you have to change from one to another – off the train, up the stairs, down the stairs, wait for another train. Surely you want a system where all of that is taken care of?

The way forward

All these considerations lead us to look at how a system based on tunnels for electric cars, where the digital control of them ensures there is never any congestion and the system takes you directly where you want to go. Naturally the car (owned or shared) being able to drive itself will park itself in a stack until it is needed. We are looking at the minimum interference at street level, a simple lift no larger than a bus stop takes you directly to your vehicle. All of this is controlled through an app so you can decide to travel when and where you want to completely feely.

It seems certain such types of systems will be implemented on existing freeways, such as the I-5 Cascadia Corridor project (Seattle – Vancouver). A gradual introduction may also come at particular pinch points such as tunnels and bridges into Manhattan, or approaches to London, or any city where technology is seen as key enabler of better urban living.

The CarTube.global is an exploration of how a system could look and how it would revolutionize our thinking about Urban Mass Transport. PLP is actively pursuing research in this area and will be partnering with significant players in the future.

Roads take up a huge amount of space – we can rethink how mass transportation works and use streets for what they are good at – for people, not cars. We also need to properly explore technologies to reduce pollution, noise and global warming – new technologies provide us with new tools, let’s use them.