Passage: Measured data of averaged vehicle speeds (Figure 3 (a)) illustrate the phase definitions [J] and [S]. There are two spatial-temporal patterns of congested traffic with low vehicle speeds in Figure 3 (a). One pattern propagates upstream with almost constant velocity of the downstream front, moving straight through the freeway bottleneck. According to the definition [J], this pattern of congestion belongs to the "wide moving jam" phase. In contrast, the downstream front of the other pattern is fixed at a bottleneck. According to the definition [S], this pattern belongs to the "synchronized flow" phase (Figure 3 (a) and (b)). Other empirical examples of the validation of the traffic phase definitions [J] and [S] can be found in the books and, in the article as well as in an empirical study of floating car data (floating car data is also called probe vehicle data).

Question: How many spacial-temporal patterns are there?
two