Vehicle Control Systems signage at Liverpool Airport

Today's post examines the signage at Liverpool John Lennon Airport, with grateful thanks to Esmerobbo who took photographs and made measurements.

Vehicle Control Systems try and pretend that anyone who drives into the airport enters into a contract to pay them £100 if they stop on the airport roads. Here are the signs they use.

The Prankster's first observation is that only the first sign contains the name of Vehicle Control Systems. As it is a general principle that you must know who you are contracting with it is the Prankster's view that only the top sign can form a contract.

Apparently the top sign is only at the entrance to the Airport, so this is the only chance VCS have of forming a contract with the driver.

Cut-off distance

A useful publication from the Department of Transport, 'Determination of x-height',  describes how font sizes are calculated on road signs. The first observation is that drivers must be able to read signs without moving their head more than 10% from the road. This is for safety reasons. Both the Independent Parking Committee and the British Parking Association agree with this in their respective code of practices.

The publication gives calculations to show how far away the sign is when the driver must turn their head back to the road. This is known as the 'cut off distance', C

The calculation is C = S x cotangent of 10 degrees = S x 5.7
S is the offset distance, defined as the distance from the centre of the driving lane to the centre of the sign. On dual carriageways this is measured from the centre of the right-hand-most lane.

As the road is a dual carriageway, this is given as (sign width /2) + distance from sign to road + 1.5 x width of one lane. Esmerobbo has kindly provided these distances as:
S = (.80/2) + 1 + 1.5 x (4) = 7.40m

This gives C = 7.40 x 5.7 = 42.18m.

The sign can therefore only safely be read from over 42m away. As the sign is placed 4.5m from a T-junction, it can never safely be read.

Reading Time

The next consideration to examine is the number of words on the sign. DfT guidelines state that a sign should contain no more than 6 words or directions. This is the number that can be scanned safely in 4 seconds. Any more than that and the driver's eyes are off the road for too long.

Reading time R is given as 2 + N/3 seconds, where N is the number of words or directions on the sign. 2 seconds are given for the eyes to settle on the sign and start reading.

The sign contains 66 words, not including the small print at the bottom. This will take 35 seconds to read.The only possible way to read the sign would be to stop at or just after the T-Junction, but this will be a breach of the alleged contract.

The first six words, and the ones in the biggest font, are 'RESTRICTED ZONE', No stopping at any...'.

To form a contract there must be a meeting of minds. For this to take place, the driver must not only have time to read the sign, but also time to consider and digest the contract and decide whether to accept or not. In a car park, the driver can do this at their leisure; typically the operator will give 5 minutes for the driver to consider any contract and decide whether to accept or not. it is obvious that there can be no meeting of minds if the driver does not have time to read the sign, let alone have time to consider it, especially when their main focus must be on driving safely and not considering the intricacies of contract law.

Font Size

The final consideration is font size. The small print disclosing the £100 charge has capitals 4cm high and lowercase letters 3cm high.

The eyesight standards for driving are here. They require a driver to read a 8cm number plate at a distance of 20m. This translates into being able to read 4cm letters at 10m, and 3cm letters at 7.5m.

The road has a 40mph speed limit. At 40mph a vehicle travels 18 meters a second. At this speed, the sign is readable for 4/10s of a second. Two seconds are needed for 'settle time' before any words can be read, so the small print is not readable,

However, the sign is just past the junction, so generously assuming the speed is only 10mph this gives 1.6 seconds to read the sign. Sadly even this is not enough to read a single word.

There also remains the impossible conundrum that the driver must stop reading the sign at a distance of 42m, but can only read the signs once they get 7.5m away.

Guidelines

We can go back to the DfT guidelines and find out what they would recommend. The distance travelled while reading the sign R is given as:
R = reading time x speed (meters per second)

For the maximum 6 words at 40mph, we get R = 4 x 18 = 72m.
The driver therefore starts reading the sign at 72+42m (114m) and stops reading at 42m.

To read the signage at 114m, the DfT calculation for lowercase letters (known as X-height) is (100/60) x 114 = 19cm

Each lowercase letter should therefore be 19cm high.

The actual size of the biggest lowercase letter is 6cm. Therefore the font is less than 1/3 of the required size.

Conclusions

• Only one sign is capable of creating a contract
• This sign is too close to the junction to be read safely
• It contains eleven times the number of words which can be read safely
• The smallest font can never be read safely
• The biggest font is only 1/3 of the required size for vehicles travelling at the speed the road allows

In The Prankster's opinion, there is no possibility this sign can ever be said to form a contract with the driver, and the sign actually tempts drivers into unsafe driving practices, by making them turn their head too far from the road, and keeping their attention off the road for too long.

Happy Parking

The Parking Prankster