How much fuel do you save by using Expressway?

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

07 January 2024

The cabinet secretary for transport recently gazetted new toll rates for using the Nairobi Expressway. Motorists will now pay Sh500 [up from Sh360] to travel the entire length of the road from Mlolongo to Westlands – a distance of 27km. The gazette notice carried a curious statement that the charges are “exclusive of VAT”.

Now, ordinarily, this means that, at the time of payment, the customer will be charged VAT on top of the published rate. Thus, the total cost should be Sh580. However, previous gazette notices were written in the same manner, yet, the charges have always been without VAT. I understand that these tolls are “exempt from VAT”, therefore there is no need to state that the published charges are “exclusive of VAT”.

However; ss the toll rates go up, motorists have now started wondering whether there is direct financial benefit in using the Expressway. That is, does driving on the expressway save fuel? Let’s find out.

The average motorcar drives for about 15km on the highway with one litre of fuel. On city roads, the distance drops down to about 10km/L. The expressway is essentially a highway while the Uhuru Highway below it is a city road.

At 5km/L, the car consumes 0.067L/km (this is simply the inverse of 15). Therefore, on the 27km-journey, it will burn 1.8L of fuel. By similar calculations we find that, at 10km/L on the city road, the car will consume 2.7L.

So, the saving on fuel is just 0.9L (2.7L – 1.38L). At the current price of Sh212, the total saving of fuel comes to about Sh190. Is it wise to spend Sh500 in order to save Sh190? The answer is obviously no! But that’s not the only consideration that motorists make when deciding whether to use the expressway. Time savings are a bigger factor.

Nevertheless, the higher the price of petrol, the greater the savings one makes by using the Expressway. We may want to know at what price of petrol the cost of using the Expressway becomes equal to the fuel savings. The answer is simply the Sh500 divided by 0.9L. This comes to about Sh555 per litre of fuel!

Is it reasonable to expect that we shall see such a price any time in the foreseeable future? I don’t think so. By the time petrol prices reach Sh555, the cost of using the Expressway will also have gone up way above Sh500 for the 27km!