PRT - Hermes

PRT and Environment

How will PRT change the way city looks?

What about pedestrians?

Energy consumption

Pollution

Noise pollution

City environment: the big picture



How will PRT change the way city looks?

Some people express doubts about PRT , claiming that all these overhead "bridges" will hide the skies.

First of all , the sky is not hidden by a narrow guideway 70cm wide , every 4-5 blocks. The sky is hidden by big blocks of flats and narrow roads. People don't like living in them , they prefer the suburbs. People prefer living in a dispersed city. A PRT system can cope with the transportation needs of such a city , Mass transit can't.

Aesthitically speeking , it's just a matter of getting used to the sight. Some won't like it but , once the system proves its benefits , the vast majority of the people will accept and like it.

The sight of the new transit system will denote a better quality of life , in sharp contrast with the sight of congestion we have today.

The sight of a PRT system will mark the civilization in a city the same way as the electric light , rather than darkness , marks the civilization in our home.



What about pedestrians?

PRT is a grade separated system therefore pedestrians will move about freely with no danger. Children may even use as a playgournd a foot-walk where guideway is located.



Energy consumption

  • Small weight
  • Low rolling friction coefficient
  • Adequate aredynamics
  • Steady speed / no stops
PRT/Hermes uses the same basic principles as the economy car racers do.

A car , for comparison , spends energy due to 3 reasons:

  1. Acceleration
  2. Rolling friction
  3. Air resistance
  1. PRT has no stops or traffic lights.It will accelerate only once per trip. A car may stop/accelarate 20-30 times during a trip (VERY conservative estimation). PRT will spend 20-30 times less energy for acceleration.
  2. Rolling friction is proportional to weight and rolling friction coefficient. PRT/Hermes will have half the weight of a car.Its steel wheels run on steel rail which have a rolling friction coefficient 15 times less than that of tires on the road.PRT will spend 30 times less energy for rolling friction.
  3. Air resistance depends on frontal crossection (a little smaller on Hermes) and the vehicle design (Hermes shape will be like that of an egg). Most importantly however it depends on speed (proportional to the square of speed).PRT 's steady speed is much better than the cars fast/slow cycles. In general it is expected that energy spend on air resistance will be less than half than that of a car.
    Note this however: In city trips air resistance is by far the smallest factor , compared to the other two.

PRT/Hermes has an overwhelming advantage (about 30 times less) in the most energy consuming factors (rolling friction , acceleration).



Pollution

PRT uses electricity and has no emissions in the city.

It is also very energy efficient which means that at the place where electricity is produced , there will be less emissions compared to any other transit solution.



Noise pollution

PRT vehicles have no noisy internal combustion engine. Even its motor is a LIM (linear induction motor).It has no moving parts and is very quiet.

Air resistance induced noise should be small , because of the relatively low speed (60-65 km/hour)

Noise comming from the rolling wheels will be greatly reduced since it will be generated inside the guideway. Noise waves will have to make multiple bounces in the guideway walls before getting out. Guideway will act as a noise absorbing sound barrier.



City environment: the big picture

Generally speaking all electric means of transportation , like electric buses , are more environment friendly than their internal combustion engined counterparts.

Those riding rails , like light rail , occupy less space and are more quiet too.

And of course those that run on their dedicated guidway , like subways , present the smallest disturbance to city inhabitants.

All these are nice and good.
But can we persuade people to use such systems instead of cars and motorcycles? The answer is NO! As explained in Cost:The big Picture , investing in mass transit hoping to reduce car usage is a waste of money

A nice setting , people walking lazily and green grass. Almost no noisy and polluting cars. Can we see something like that in Athens?

If cars are banned yes. If not people will always prefer their much faster automobiles.

Another nice picture. PRT is environment friendly as fast as a car Event if there is no congestion , most people will use PRT because it will be cheaper , easy and safe.