Create a smart playlist with all unplayed podcasts. By using this playlist you no longer have to find the next podcast on your iPhone whilst driving back home. Make sure that you include the smart playlist on the Podcast tab of your iPhone, iPad or iPod Touch.
Update:
Although this seemed a great solution in theory, there are some issues with this approach in practice. As diskspace on the iPhone is at a premium you will have to limit the amount of podcast data stored on your device. However, because there is not an option to keep 1 unplayed episode per podcast in the smart playlist editor you have to set the amount of diskspace used. When you have several podcasts and some are updated more frequently then others you will end up for some podcasts not being on your device and others that are continuously listened to. Therefore I opted for ">InstaCast which caches 1 episode per podcast and comes with continuous playback in its latest update.