Toyota has made digital radio a standard feature in three of its locally built cars and the commercial broadcasters are giving five away in a promotion to mark three years of permanent digital broadcasts - one in each of the five mainland state capitals.

The industry peak body, Commercial Radio Australia, says 34 per cent of all radio listening occurs in motor vehicles.

The three models are the hybrid Camry HL, with a drive-away price of $45,357, a regular petrol Camry Atara SL ($43,915) and the Aurion V6 Presara ($54,215). Toyota's luxury marque, Lexus, also boasts digital radio as a standard feature in its imported GS series but Lexus is not involved in the giveaway.

However, the competition winners can be satisfied that each of the three Toyotas to choose from is equipped with a superior radio system than that of the $108,981 Lexus GS450h.

While the Lexus has a 31-centimetre widescreen display in the centre of the dashboard and a 17-speaker Mark Levinson sound system, the Toyotas have a much simpler radio interface, with a touchscreen.

The systems in the Lexus and Toyotas have an unusual directory tree, in which the DAB+ stations are selected according to which very high frequency (VHF) channel they are broadcast on - 9A, 9B or 9C.

It is a complex way to change stations, and will likely be fixed in later software updates.

There is problem when tuning from a station on 9C to 9A or vice versa: if the listener mistakenly seeks a channel other than 9B, the radio scans through all VHF channels, resulting in many seconds of silence.

In a test by The Age, the GS450h took 23 seconds to complete the scan and the Toyota Aurion V6 Presara took nine seconds, perhaps more comparable to a scan on FM or AM. However, the Lexus and Toyota car radios offer the time-shift feature, to repeat a news bulletin or football score.