Ranking Reasoning:
Let's evaluate each diagram based on the criteria provided:

### Diagram 1:
- **Strengths:** Uses color coding to indicate clear and blocked status, which is intuitive.
- **Weaknesses:** The layout is not very intuitive; cars are placed below the curbs, which might confuse the viewer. Text readability is low due to overlap.

### Diagram 2:
- **Strengths:** Clear layout with cars inside curbs, good use of color coding for status.
- **Weaknesses:** Text overlaps with the cars, making it hard to read. The vertical layout might not be as intuitive.

### Diagram 3:
- **Strengths:** Uses color coding effectively to show status.
- **Weaknesses:** Cars are not placed inside curbs, which can be confusing. Text readability is low due to overlap.

### Diagram 4:
- **Strengths:** Simple layout with cars inside curbs.
- **Weaknesses:** Lacks color coding for status, making it less intuitive. Text is small and hard to read.

### Diagram 5:
- **Strengths:** Good use of color coding and clear layout with cars inside curbs.
- **Weaknesses:** Text overlaps with the cars, reducing readability.

### Diagram 6:
- **Strengths:** Uses color coding for status.
- **Weaknesses:** Cars are not placed inside curbs, and text readability is low due to overlap.

### Diagram 7:
- **Strengths:** Uses color coding effectively and has a clear layout with cars inside curbs.
- **Weaknesses:** Text is small and overlaps, making it hard to read.

### Diagram 8:
- **Strengths:** Clear layout with cars inside curbs, good use of color coding.
- **Weaknesses:** Text overlaps with the cars, reducing readability.

### Ranking:
```ranking
2, 5, 8, 7, 1, 3, 4, 6
```

### Explanation:
1. **Diagram 2** is ranked highest due to its clear layout and effective use of color coding, despite some text overlap.
2. **Diagram 5** follows closely, with a good layout and color coding, but suffers from text overlap.
3. **Diagram 8** has a clear layout and good color coding, but text readability is an issue.
4. **Diagram 7** is clear and uses color coding well, but text readability is a problem.
5. **Diagram 1** uses color coding effectively but has a confusing layout and text overlap.
6. **Diagram 3** uses color coding but has a confusing layout and text overlap.
7. **Diagram 4** is simple but lacks color coding and has small, hard-to-read text.
8. **Diagram 6** uses color coding but has a confusing layout and text overlap.
