According to Mohr and Fourie (2004), the tax burden should be distributed equally among the various taxpayers. Equity (fairness) can be described using two principles, the ability to pay principle and the benefits received principle. The benefits-received principle, according to Case et al (2014), is a theory of fairness/equity that states that citizens should contribute in proportion to the benefits they receive from public spending. E-Tolling is a good example of this as it complies with the benefits received principle, whereby e-tolling users pay for the use of toll roads in proportion to the benefits they derive/receive. SANRAL charges a tax/duty to be paid for the use of the road. If you use the road more than other users you pay more, if you use the road less you pay less. What you pay is proportional to your usage. The money raised is then used to build and maintain toll roads. In the case of electronic tolling, it is regressive and unfair because the poor pay a higher percentage of their income than the rich. According to Case et al (2014), the ability to pay principle is a fairness/equity theory that citizens should bear tax burdens in line with their ability to pay taxes. Those who can earn more should pay more, the rich should subsidize the poor, as happens with income tax. This has not been implemented in the case of electronic tolling as SANRAL is applying the benefits received principle for road user tolling. It might have been applicable if SANRAL had decided to use a “road access” charge collected through SARS, deductible directly from income as PAYE. Only then will the principle of ability to pay apply. This is progressive in nature and is a fair system for the poor as everyone pays the relevant sum based on their income and… mid-paper… the estimated monthly income is around R396 million. Raising the price slightly to 40c/km would result in monthly revenues of R528 million as the quantity will not change due to inelastic demand. However, in this case, the government received only about 9% of the invoiced revenue while the rest (91%) went uncollected. It won't be easy for SANRAL to get that money paid as it has already threatened users with legal action or jail time and yet users don't pay. Consumer SurplusConsumer surplus is the difference between the maximum price a consumer is willing to pay and the current market price of goods or services (Case et al, 2014). In this scenario, consumer surplus will be significantly reduced as users paid nothing for the roads before the upgrade works (except taxes and fuel levies, which they are still paying).).