Honolulu’s Handi-Van system has been on a bumpy ride of its own for more than 20 years — with vehicles often driven far past recommended age and mileage limits, too few vans to meet rider demand, and a dispatch system that is alarmingly outdated and inadequate.

Handi-Van riders, who live with disabilities that make it difficult to access TheBus, have for years suffered through calls for service that are dropped or subject to long waits; vehicles that don’t come on schedule, forcing riders to wait outside in the dark or in the hot sun; or unavailability of the popular service, which can fill up despite a client’s need for transport to a medical appointment or other vital purpose.

The latest negative development: Vans ordered to replace an aging fleet are being delivered behind schedule, adding to a pileup of difficulties that drag down Handi-Van performance. In March, just 67% of Handi-Vans were rideable. Any figure below 80% should be considered a crisis, or as Transportation Services Director Roger Morton told the City Council last year, a “warning sign.”

Low fleet numbers affect availability for riders. That’s a problem that needs addressing by keeping to a deployment and replacement schedule that doesn’t rely on continued operation of outdated vehicles.

The city should also thoroughly explore its future alternatives for obtaining fleet vehicles — including the prospect of diversifying the fleet so that specialized, highly expensive vans designed for wheelchairs are deployed only where absolutely needed.

That means less-costly vehicles safe and suitable for certain riders — the visually impaired but physically able, for example, who do not need wheelchair transport — should be used where possible.

Exploring various types of vehicles — and vehicle sources — can protect the city from being forced into crisis mode if a sole vendor can’t meet needs.

Honolulu is legally required by the federal Americans with Disabilities Act (ADA) to provide a public transportation option that meets the needs of riders with disabilities. And the Handi-Van is a lifeline for many residents; budgeted for more than 200 vehicles, it serves about 3,000 riders each day. Beyond federal law, the city must make the experience of these thousands of riders a priority; that will guide reforms.

Aside from an adequate supply of vehicles, another critical factor is the Handi-Van’s dispatch system. Incredibly, in this age of cell phones, Uber and GPS, the system in place so far does not track vehicles’ exact locations or allow for online reservations — so riders are forced to wait outside with only a rough idea, even no idea, of when a vehicle might arrive.

That sad state of affairs is being forced to change, however: In January, the U.S. Department of Justice forged an agreement with the city to put an end to long waits for trip reservations over the next three years. To meet this requirement, the city will have to modernize.

The agreement, reached to settle a rider’s complaint, mandates that 95% of reservation calls be answered within three minutes. Basically all calls — 99% — must be answered within five minutes.

The city has already publicly committed to spend $750,000 for a new software system to reserve rides online. The new system and the new vans are sorely needed, as disabled Handi-Van riders have continued to report disturbing problems with unpredictable scheduling and communications.

The agreement pushes the city to make changes that should have been addressed years ago, before Mayor Rick Blangiardi assumed office. Still, that will be all to the good if this administration applies its stated commitment to fresh solutions and the use of updated technology to improve service. The city must attack this problem with vigor, get a grip on the scope of the issue and upgrade the entire Handi-Van system, from procurement of vehicles to dispatch.