With thousands of new visitors cramming Austin streets for South by Southwest, the need for transportation options is as clear as ever. While the city has taxis, buses, pedicabs and short term car rentals, the primary choice has always been rideshare apps.

Saturday night, the influx of SXSW visitors and steady rain created what Fasten CEO Kirill Evdakov called "a perfect storm."

Fasten was just one of the apps to be overwhelmed and shut down temporarily Saturday. Evdakov said it was a combination of rain and more than 12 times the normal demand in some locations.

Evdakov and his team were able to quadruple the Fasten server capacity and were "down" from 8:20 p.m. to 9:15 p.m.

Other apps including non-profit RideAustin did not fare so well. That app remained offline or unavailable for multiple hours.

Evdakov wrote a statement apologizing to riders and drivers alike and explaining how the situation arose:

"What I’d say to every Fasten driver and rider eye-to-eye is the following: We are truly sorry that several hundred of our customers experienced difficulties requesting rides on Saturday night between 8:20pm & 9:15pm. Service interruptions are completely unacceptable, no matter how intermittent they may be. The only number that matters to customers is one. One request, one ride.

This is the first time in SXSW history that a single rideshare app had to handle the demand during the busiest time of the week for locals, tens of thousands of SXSW visitors, pouring rain and non-functional competitive apps, all of which came together at the same time to form a perfect storm. Once we quadrupled our server capacity, we were able to handle sustained 12x volumes for 3 hours until our competitors recovered after midnight and picked up some of it. As a result, we are confident that the rest of the festival will go smoothly.

We understand riders do not wish to pay higher rates. And we couldn’t agree more. However, we can’t bend the laws of supply & demand (as well as physics) yet. Special events like SXSW, ACL, F1 and Longhorn games bring about even greater imbalance when demand spikes by a double digit factor. Under these extreme circumstances, the inelasticity of supply coupled with traffic forces the price increases in order to ensure availability for those who absolutely must use the service. At this stage we choose to guarantee availability at the expense of affordability.

Finally, when it comes to higher (Boost) rates, Fasten is fundamentally different from our percentage-based competitors. While they take 20-28% from drivers for all rides, we charge them only $0.99 per ride, even from Boost rides. By definition, this translates into higher driver earnings at lower Boost multipliers. With our model, both sides win."