Users of car-hailing appsare being charged extra in about 20 percent of cases, the Shanghai Consumer Council said.

The council announced its findings after a test involving 128 rides from three hailing applications —Didi Chuxing, CAR Inc and Yidao Yongche.

Of the 121 orders completed, 24, or 19.8 percent, involved extra charges, making the final charge between 1.1 to 1.4 times the normal fare, according to the council.

CAR Inc wasfound to have the highest extra charge rate, at72 percent, with a third of these farescharging 1.6 times the normal fare, the highest charge of all three platforms, the council said.

Council officials also found that in 6 percent of orders on Yidao and Didi apps, the vehicles arriving were different from that shown on theapp, and that mostof them should have been charged at a cheaper rate.

In addition, the charge for threeYidaoorders was found to 0.3 yuan more per kilometer than the app had indicated, according to the council.

The hailing success rate of these apps was 94.5 percent, and in 11.9 percent of orders, the real fare was higher than that estimated on theapps, with Didi having the highest fare deviation rate, reaching 14.7 percent, according to the council.

The deviation in distance between theapps' estimation and the real situation was 9.1 percent, with Yidao showing the poorest performance, while the time deviation rate was 44.6 percent.

CAR Inc had a 79.4 percent time deviation rate because it did not consider peak hours in its estimation system, the council said.

Didihad the highest customer dissatisfaction rate at 22.8 percent, according to the council.

"Car hailing apps are gaining in popularity and they provide a new and convenient option for transportation, but their operators should also tackle these problems and enhance management at the same time," said Tao Ailian, secretary-general of the council.

The Shanghai Transportation Commission said that unlike taxis which have a standard price model regulated by the authority, price adjustments of online ride-hailing apps on some occasions such as rush hour or Spring Festival travel peaks are compliant market behavior. But it is prohibited for a driver to decide to charge extra fare. In such cases, passengers should report to the ride-hailing firms and the firms should punish drivers accordingly.