Answers.Body: <p>I asked one of the set designers at LEGO, Samuel Johnson, on Twitter. Here is our conversation:</p>
  <blockquote>
  <p>This to aid in the building flow for children aged 5 and up. Easy to spot on the page, easy to find in the pile of bricks :)</p>
  <p>— <a href="https://twitter.com/Spider_Sam_LEGO/status/1037914372897681409" rel="noreferrer">https://twitter.com/Spider_Sam_LEGO/status/1037914372897681409</a></p>
  </blockquote>
  
  <blockquote>
  <p>Ah! Do both the colour and the shape (studless vs studded) contribute to this?</p>
  <p>— <a href="https://twitter.com/NOVALISTIC/status/1037914613847740416" rel="noreferrer">https://twitter.com/NOVALISTIC/status/1037914613847740416</a></p>
  </blockquote>
  
  <blockquote>
  <p>Depends on the model :)</p>
  <p>5year olds aren’t very strong, so it can make it easier to build</p>
  <p>— <a href="https://twitter.com/Spider_Sam_LEGO/status/1037967767847227392" rel="noreferrer">https://twitter.com/Spider_Sam_LEGO/status/1037967767847227392</a></p>
  </blockquote>
  
  <blockquote>
  <p>That makes sense. Too many stud-and-tube connections can make building difficult even for me at times. Thanks for answering!</p>
  <p>— <a href="https://twitter.com/NOVALISTIC/status/1037994518295994368" rel="noreferrer">https://twitter.com/NOVALISTIC/status/1037994518295994368</a></p>
  </blockquote>
  <p>So, it's an interaction of several factors including ease of following the instructions, as well as ease of physically attaching elements together (and, presumably in turn, disassembling them).</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2018-09-07T09:30:44.587Z
Answers.LastActivityDate: 2018-09-07T09:37:20.300Z
Answers.LastEditDate: 2020-06-18T08:28:58.637Z
Answers.UserDisplayName: LegoSonicBoy
Body: <p>While building <a href="https://brickset.com/sets/60150-1" rel="noreferrer">60150 Pizza Van</a>, I noticed that the first few steps of building the eponymous vehicle have you place lime green 1x2 tiles in specific positions and black 1x2 plates in others:</p>
  
  <p><img src="https://i.sstatic.net/udcQu.jpg" alt=""></p>
  
  <p>These then get covered completely by light grey 2x16 plates (although you can still see them just behind the wheels and mudguards of the finished model):</p>
  
  <p><img src="https://i.sstatic.net/K3iQW.jpg" alt=""></p>
  
  <p>A similar use of tiles appears in other LEGO City vehicles, such as the ambulance in <a href="https://brickset.com/sets/60204-1" rel="noreferrer">60204 LEGO City Hospital</a>.</p>
  
  <p>Why are tiles used in parts of the chassis construction? Is it to (slightly) reduce the number of studs holding onto the tubes of the 2x16 plates, thereby making them easier to remove when taking things apart later?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-09-06T07:58:52.907Z
Comments.Text: Note that I'm not asking about the use of lime green - [that's to make it easier to distinguish them from the black 1x2 plates](https://bricks.stackexchange.com/questions/2895/why-do-some-sets-contain-parts-of-an-unrelated-colour-that-are-hidden-on-the-fin).
Comments.UserDisplayName: LegoSonicBoy
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2018-09-06T11:35:03.333Z
Comments.Text: Looking at the carplates of these two examples, we can guess the designer's initials, BD (for the pizza van) and ER (for the ambulance), so probably not the same designer. But ease of disassembly seems a likely explanation. TLG does some play tests with the target age, and if "it's difficult to remove this section" comes up in the feedback, the designer might come up with this kind of solution. Your intuition seems good to me.
Comments.UserDisplayName: rienafairefr
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-06-04T10:31:33.590Z
Comments.Text: @rienafairefr: Is that connection between designer's initials and carplates confirmed? Otherwise, I'd have guessed "ER" simply stands for "emergency room".
Comments.UserDisplayName: O. R. Mapper
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-06-04T10:48:32.073Z
Comments.Text: @O. R. Mapper: Yes, this is true of many sets across several themes (City, Friends, Creator Expert to name a few), and in some cases the designers themselves have confirmed this.
Comments.UserDisplayName: LegoSonicBoy
Tags: <building><design><city>
Title: Why do some LEGO City vehicles have tiles in their chassis?
UserDisplayName: LegoSonicBoy
ThreadText: # Why do some LEGO City vehicles have tiles in their chassis?
  
  (Asked by: username_0 on 2018-09-06)
  
  While building [60150 Pizza Van](https://brickset.com/sets/60150-1), I noticed that the first few steps of building the eponymous vehicle have you place lime green 1x2 tiles in specific positions and black 1x2 plates in others:
  
  ![](https://i.sstatic.net/udcQu.jpg)
  
  These then get covered completely by light grey 2x16 plates (although you can still see them just behind the wheels and mudguards of the finished model):
  
  ![](https://i.sstatic.net/K3iQW.jpg)
  
  A similar use of tiles appears in other LEGO City vehicles, such as the ambulance in [60204 LEGO City Hospital](https://brickset.com/sets/60204-1).
  
  Why are tiles used in parts of the chassis construction? Is it to (slightly) reduce the number of studs holding onto the tubes of the 2x16 plates, thereby making them easier to remove when taking things apart later?
  
  **Tags:** building, design, city
  > **Comments:**
  > **username_0**: Note that I'm not asking about the use of lime green - [that's to make it easier to distinguish them from the black 1x2 plates](https://bricks.stackexchange.com/questions/2895/why-do-some-sets-contain-parts-of-an-unrelated-colour-that-are-hidden-on-the-fin).  
  > **username_1**: Looking at the carplates of these two examples, we can guess the designer's initials, BD (for the pizza van) and ER (for the ambulance), so probably not the same designer. But ease of disassembly seems a likely explanation. TLG does some play tests with the target age, and if "it's difficult to remove this section" comes up in the feedback, the designer might come up with this kind of solution. Your intuition seems good to me.  
  > **username_2**: @rienafairefr: Is that connection between designer's initials and carplates confirmed? Otherwise, I'd have guessed "ER" simply stands for "emergency room".  
  > **username_0**: @O. R. Mapper: Yes, this is true of many sets across several themes (City, Friends, Creator Expert to name a few), and in some cases the designers themselves have confirmed this.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_0 on 2018-09-07. Score: 12 | Accepted answer
  
  I asked one of the set designers at LEGO, Samuel Johnson, on Twitter. Here is our conversation:
  
  > This to aid in the building flow for children aged 5 and up. Easy to spot on the page, easy to find in the pile of bricks :)
  >
  > — <https://twitter.com/Spider_Sam_LEGO/status/1037914372897681409>
  
  > Ah! Do both the colour and the shape (studless vs studded) contribute to this?
  >
  > — <https://twitter.com/NOVALISTIC/status/1037914613847740416>
  
  > Depends on the model :)
  >
  > 5year olds aren’t very strong, so it can make it easier to build
  >
  > — <https://twitter.com/Spider_Sam_LEGO/status/1037967767847227392>
  
  > That makes sense. Too many stud-and-tube connections can make building difficult even for me at times. Thanks for answering!
  >
  > — <https://twitter.com/NOVALISTIC/status/1037994518295994368>
  
  So, it's an interaction of several factors including ease of following the instructions, as well as ease of physically attaching elements together (and, presumably in turn, disassembling them).
  
  
  ---
  
  