Michael Kennedy is a leading expert on Lean and Product Development. He is the author of Product Development for the Lean Enterprise: Why Toyota's System Is Four Times More Productive and How You Can Implement It, a book you definitely want on your bookshelf if you are interested in Lean Product Development.
Toyota engineers take a different approach. Their overarching goal is to generate a constant flow of new products, so instead of assigning a team to focus on developing one in particular, work is concentrated at the subsystem level. The idea is that subsystems can be mixed and matched to create a whole host of possible new products, fostering creative possibilities.
Even acknowledging that something won't work is good because it identifies a path for engineers to avoid in the future. You might say, then, that the Toyota System is "knowledge-based" as contrasted with the usual western system, which is perhaps more aptly labeled "process-based."
Perhaps one of the most appealing aspects of the Toyota system is that it lowers the risk of failure
Take a read and then get a copy of Implementing Toyota's Product Development System.